@article{kang_x-y_and_j-f_mao_gamete_2001,
	title = {Gamete fertility morphological variations in offsprings of triploid clones of {Populus} tomentosa},
	volume = {23},
	shorttitle = {Gamete fertility morphological variations in offsprings of triploid clones of {Populus} tomentosa},
	author = {Kang, X.-Y. {and} J.-F. Mao},
	year = {2001},
	pages = {20--23},
}

@article{karpinska_novel_2001,
	title = {A {Novel} {Superoxide} {Dismutase} with a {High} {Isoelectric} {Point} in {Higher} {Plants}. {Expression}, {Regulation}, and {Protein} {Localization}},
	volume = {126},
	url = {https://www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC117165/},
	doi = {10/d7rhjj},
	abstract = {Several isoforms of superoxide dismutase (SOD) with a high isoelectric point (pI) have been identified by isoelectric focusing chromatography in protein extracts from Scots pine (Pinus sylvestris) needles. One of these isoforms, a CuZn-SOD with a pI of ...},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Plant Physiology},
	author = {Karpinska, Barbara and Karlsson, Marlene and Schinkel, Helga and Streller, Steffen and Süss, Karl-Heinz and Melzer, Michael and Wingsle, Gunnar},
	month = aug,
	year = {2001},
	pmid = {11500564},
	note = {Publisher: Oxford University Press},
	pages = {1668},
}

Several isoforms of superoxide dismutase (SOD) with a high isoelectric point (pI) have been identified by isoelectric focusing chromatography in protein extracts from Scots pine (Pinus sylvestris) needles. One of these isoforms, a CuZn-SOD with a pI of ...

@article{uggla_function_2001,
	title = {Function and {Dynamics} of {Auxin} and {Carbohydrates} during {Earlywood}/{Latewood} {Transition} in {Scots} {Pine1}},
	volume = {125},
	issn = {0032-0889},
	url = {https://doi.org/10.1104/pp.125.4.2029},
	doi = {10/csvzgg},
	abstract = {In temperate regions the annual pattern of wood development is characterized by the formation of radially narrow and thick walled latewood cells. This takes place at the later part of the growing season when cambial cell division declines. To gain new insight into the regulation of this process, micro-analytical techniques were used to visualize the distribution of indole-3-acetic acid (IAA), soluble carbohydrates, and activities of sucrose (Suc)-metabolizing enzymes across the cambial region tissues in Scots pine (Pinus sylvestris). The total amount of IAA in the cambial region did not change with latewood initiation. But its radial distribution pattern was altered, resulting in an increased concentration in the cambial meristem and its recent derivatives. Thus, initiation of latewood formation and cessation of cambial cell division is not a consequence of decreased IAA concentrations in dividing and expanding cells. Rather, IAA most likely has a role in defining the altered developmental pattern associated with latewood formation. Carbohydrates and enzyme activities showed distinctive radial distribution patterns. Suc peaked in the phloem and decreased sharply to low levels across the cambial zone, whereas fructose and glucose reached their highest levels in the maturing tracheids. Suc synthase was the dominating Suc cleaving enzyme with a peak in the secondary wall-forming tracheids and in the phloem. Soluble acid invertase peaked in dividing and expanding cells. Suc-phosphate synthase had its highest activities in the phloem. Activities of cell wall bound invertase were low. The absence of major seasonal variations indicates that carbohydrate availability is not a trigger for latewood initiation. However, steep concentration gradients of the sugars suggest a role for sugar signaling in vascular development.},
	number = {4},
	urldate = {2021-11-02},
	journal = {Plant Physiology},
	author = {Uggla, Claes and Magel, Elisabeth and Moritz, Thomas and Sundberg, Björn},
	month = apr,
	year = {2001},
	pages = {2029--2039},
}

In temperate regions the annual pattern of wood development is characterized by the formation of radially narrow and thick walled latewood cells. This takes place at the later part of the growing season when cambial cell division declines. To gain new insight into the regulation of this process, micro-analytical techniques were used to visualize the distribution of indole-3-acetic acid (IAA), soluble carbohydrates, and activities of sucrose (Suc)-metabolizing enzymes across the cambial region tissues in Scots pine (Pinus sylvestris). The total amount of IAA in the cambial region did not change with latewood initiation. But its radial distribution pattern was altered, resulting in an increased concentration in the cambial meristem and its recent derivatives. Thus, initiation of latewood formation and cessation of cambial cell division is not a consequence of decreased IAA concentrations in dividing and expanding cells. Rather, IAA most likely has a role in defining the altered developmental pattern associated with latewood formation. Carbohydrates and enzyme activities showed distinctive radial distribution patterns. Suc peaked in the phloem and decreased sharply to low levels across the cambial zone, whereas fructose and glucose reached their highest levels in the maturing tracheids. Suc synthase was the dominating Suc cleaving enzyme with a peak in the secondary wall-forming tracheids and in the phloem. Soluble acid invertase peaked in dividing and expanding cells. Suc-phosphate synthase had its highest activities in the phloem. Activities of cell wall bound invertase were low. The absence of major seasonal variations indicates that carbohydrate availability is not a trigger for latewood initiation. However, steep concentration gradients of the sugars suggest a role for sugar signaling in vascular development.

@article{heineke_metabolic_2001,
	title = {Metabolic response of potato plants to an antisense reduction of the {P}-protein of glycine decarboxylase},
	volume = {212},
	issn = {1432-2048},
	url = {https://doi.org/10.1007/s004250000460},
	doi = {10/cw9pkv},
	abstract = {Potato (Solanum tuberosum L. cv. Desiré) plants with reduced amounts of P-protein, one of the subunits of glycine decarboxylase (GDC), have been generated by introduction of an antisense transgene. Two transgenic lines, containing about 60–70\% less P-protein in the leaves compared to wild-type potato, were analysed in more detail. The reduction in P-protein amount led to a decrease in the ability of leaf mitochondria to decarboxylate glycine. Photosynthetic and growth rates were reduced but the plants were viable under ambient air and produced tubers. Glycine concentrations within the leaves were elevated up to about 100-fold during illumination. Effects on other amino acids and on sucrose and hexoses were minor. Nearly all of the glycine accumulated during the day was metabolised during the following night. The data suggest that the GDC operates far below substrate saturation under normal conditions thus allowing a flexible and fast response to changes in the environment.},
	language = {en},
	number = {5},
	urldate = {2021-11-02},
	journal = {Planta},
	author = {Heineke, Dieter and Bykova, Natalia and Gardeström, Per and Bauwe, Hermann},
	month = apr,
	year = {2001},
	pages = {880--887},
}

Potato (Solanum tuberosum L. cv. Desiré) plants with reduced amounts of P-protein, one of the subunits of glycine decarboxylase (GDC), have been generated by introduction of an antisense transgene. Two transgenic lines, containing about 60–70% less P-protein in the leaves compared to wild-type potato, were analysed in more detail. The reduction in P-protein amount led to a decrease in the ability of leaf mitochondria to decarboxylate glycine. Photosynthetic and growth rates were reduced but the plants were viable under ambient air and produced tubers. Glycine concentrations within the leaves were elevated up to about 100-fold during illumination. Effects on other amino acids and on sucrose and hexoses were minor. Nearly all of the glycine accumulated during the day was metabolised during the following night. The data suggest that the GDC operates far below substrate saturation under normal conditions thus allowing a flexible and fast response to changes in the environment.

@article{ciereszko_phosphate_2001,
	title = {Phosphate status affects the gene expression, protein content and enzymatic activity of {UDP}-glucose pyrophosphorylase in wild-type and pho mutants of {Arabidopsis}},
	volume = {212},
	issn = {1432-2048},
	url = {https://doi.org/10.1007/s004250000424},
	doi = {10/ct6jfd},
	abstract = {The effects of inorganic phosphate (Pi) deficiency on the expression of the UDP-glucose pyrophosphorylase (UGPase) gene (Ugp), involved in sucrose synthesis/metabolism, and on carbohydrate status were investigated in different tissues of Arabidopsis thaliana (L.) Heynh. For leaves, a decrease in internal Pi status caused by growth of plants on a medium lacking Pi (−P conditions) led to an increase in the overall content of glucose and starch, but had little effect on sucrose content. The Pi deficiency also led to an increased carbohydrate content in stems/flowers, but not in roots. The expression of Ugp was upregulated in both leaves and roots, but not in stems/flowers. The effects of Pi status on Ugp expression were confirmed using leaves of both pho1-2 and pho2-1 mutants of Arabidopsis (Pi-deficient and Pi-accumulating, respectively) and by feeding the leaves with d-mannose, which acts as a sink for Pi. The Pi-status-dependent changes in Ugp expression followed the same patterns as those of ApS, a gene encoding the small subunit of ADP-glucose pyrophosphorylase, a key enzyme of starch synthesis. The changes in Ugp mRNA levels, depending on internal Pi status, were generally correlated with changes in UGPase protein content and enzymatic activity. This was demonstrated both for wild-type plants grown under Pi-deficiency and for Pi mutants. The data suggest that, under Pi-deficiency, UGPase represents a transcriptionally regulated step in sucrose synthesis/metabolism, involved in homeostatic mechanisms readjusting the nutritional status of a plant under Pi-stress conditions.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Planta},
	author = {Ciereszko, Iwona and Johansson, Henrik and Hurry, Vaughan and Kleczkowski, Leszek A.},
	month = mar,
	year = {2001},
	pages = {598--605},
}

The effects of inorganic phosphate (Pi) deficiency on the expression of the UDP-glucose pyrophosphorylase (UGPase) gene (Ugp), involved in sucrose synthesis/metabolism, and on carbohydrate status were investigated in different tissues of Arabidopsis thaliana (L.) Heynh. For leaves, a decrease in internal Pi status caused by growth of plants on a medium lacking Pi (−P conditions) led to an increase in the overall content of glucose and starch, but had little effect on sucrose content. The Pi deficiency also led to an increased carbohydrate content in stems/flowers, but not in roots. The expression of Ugp was upregulated in both leaves and roots, but not in stems/flowers. The effects of Pi status on Ugp expression were confirmed using leaves of both pho1-2 and pho2-1 mutants of Arabidopsis (Pi-deficient and Pi-accumulating, respectively) and by feeding the leaves with d-mannose, which acts as a sink for Pi. The Pi-status-dependent changes in Ugp expression followed the same patterns as those of ApS, a gene encoding the small subunit of ADP-glucose pyrophosphorylase, a key enzyme of starch synthesis. The changes in Ugp mRNA levels, depending on internal Pi status, were generally correlated with changes in UGPase protein content and enzymatic activity. This was demonstrated both for wild-type plants grown under Pi-deficiency and for Pi mutants. The data suggest that, under Pi-deficiency, UGPase represents a transcriptionally regulated step in sucrose synthesis/metabolism, involved in homeostatic mechanisms readjusting the nutritional status of a plant under Pi-stress conditions.

@article{kleczkowski_new_2001,
	title = {A new player in the starch field},
	volume = {39},
	issn = {0981-9428},
	url = {https://www.sciencedirect.com/science/article/pii/S0981942801012943},
	doi = {10/dtg44w},
	abstract = {A possible role of a newly discovered ADP-glucose pyrophosphatase (AGPPase) is discussed in the context of starch synthesis. The enzyme hydrolyses ADP-glucose (starch precursor) and may potentially divert the flow of carbon from starch synthase, resulting in a ‘futile cycle’ when ‘coupled’ with ADP-glucose pyrophosphorylase. The activity of AGPPase is inversely related to starch yield in sink tissues, and may be prone to inhibition by Pi and certain other products of the starch pathway. The AGPPase likely belongs to a ‘nudix’ family of enzymes that in animal tissues and yeast are known to regulate levels of activated sugars. Some strategies for future research are underlined.},
	language = {en},
	number = {9},
	urldate = {2021-11-02},
	journal = {Plant Physiology and Biochemistry},
	author = {Kleczkowski, Leszek A.},
	month = sep,
	year = {2001},
	keywords = {ADP-glucose pyrophosphatase, ADP-glucose pyrophosphorylase, nudix hydrolase, starch synthase},
	pages = {759--761},
}

A possible role of a newly discovered ADP-glucose pyrophosphatase (AGPPase) is discussed in the context of starch synthesis. The enzyme hydrolyses ADP-glucose (starch precursor) and may potentially divert the flow of carbon from starch synthase, resulting in a ‘futile cycle’ when ‘coupled’ with ADP-glucose pyrophosphorylase. The activity of AGPPase is inversely related to starch yield in sink tissues, and may be prone to inhibition by Pi and certain other products of the starch pathway. The AGPPase likely belongs to a ‘nudix’ family of enzymes that in animal tissues and yeast are known to regulate levels of activated sugars. Some strategies for future research are underlined.

@article{savitch_cold_2001,
	title = {Cold acclimation of {Arabidopsis} thaliana results in incomplete recovery of photosynthetic capacity, associated with an increased reduction of the chloroplast stroma},
	volume = {214},
	issn = {1432-2048},
	url = {https://doi.org/10.1007/s004250100622},
	doi = {10/bsfvpb},
	abstract = {The effects of short-term cold stress and long-term cold acclimation on the light reactions of photosynthesis were examined in vivo to assess their contributions to photosynthetic acclimation to low temperature in Arabidopsis thaliana (L.) Heynh.. All photosynthetic measurements were made at the temperature of exposure: 23 °C for non-acclimated plants and 5 °C for cold-stressed and cold-acclimated plants. Three-day cold-stress treatments at 5 °C inhibited light-saturated rates of CO2 assimilation and O2 evolution by approximately 75\%. The 3-day exposure to 5 °C also increased the proportion of reduced QA by 50\%, decreased the yield of PSII electron transport by 65\% and decreased PSI activity by 31\%. In contrast, long-term cold acclimation resulted in a strong but incomplete recovery of light-saturated photosynthesis at 5 °C. The rates of light-saturated CO2 and O2 gas exchange and the in vivo yield of PSII activity under light-saturating conditions were only 35–40\% lower, and the relative redox state of QA only 20\% lower, at 5 °C after cold acclimation than in controls at 23 °C. PSI activity showed full recovery during long-term cold acclimation. Neither short-term cold stress nor long-term cold acclimation of Arabidopsis was associated with a limitation in ATP, and both treatments resulted in an increase in the ATP/NADPH ratio. This increase in ATP/NADPH was associated with an inhibition of PSI cyclic electron transport but there was no apparent change in the Mehler reaction activity in either cold-stressed or cold-acclimated leaves. Cold acclimation also resulted in an increase in the reduction state of the stroma, as indicated by an increased total activity and activation state of NADP-dependent malate dehydrogenase, and increased light-dependent activities of the major regulatory enzymes of the oxidative pentose-phosphate pathway. We suggest that the photosynthetic capacity during cold stress as well as cold acclimation is altered by limitations at the level of consumption of reducing power in carbon metabolism.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Planta},
	author = {Savitch, Leonid V. and Barker-Åstrom, Johan and Ivanov, Alexander G. and Hurry, Vaughan and Öquist, Gunnar and Huner, Norman P. and Gardeström, Per},
	month = dec,
	year = {2001},
	pages = {295--303},
}

The effects of short-term cold stress and long-term cold acclimation on the light reactions of photosynthesis were examined in vivo to assess their contributions to photosynthetic acclimation to low temperature in Arabidopsis thaliana (L.) Heynh.. All photosynthetic measurements were made at the temperature of exposure: 23 °C for non-acclimated plants and 5 °C for cold-stressed and cold-acclimated plants. Three-day cold-stress treatments at 5 °C inhibited light-saturated rates of CO2 assimilation and O2 evolution by approximately 75%. The 3-day exposure to 5 °C also increased the proportion of reduced QA by 50%, decreased the yield of PSII electron transport by 65% and decreased PSI activity by 31%. In contrast, long-term cold acclimation resulted in a strong but incomplete recovery of light-saturated photosynthesis at 5 °C. The rates of light-saturated CO2 and O2 gas exchange and the in vivo yield of PSII activity under light-saturating conditions were only 35–40% lower, and the relative redox state of QA only 20% lower, at 5 °C after cold acclimation than in controls at 23 °C. PSI activity showed full recovery during long-term cold acclimation. Neither short-term cold stress nor long-term cold acclimation of Arabidopsis was associated with a limitation in ATP, and both treatments resulted in an increase in the ATP/NADPH ratio. This increase in ATP/NADPH was associated with an inhibition of PSI cyclic electron transport but there was no apparent change in the Mehler reaction activity in either cold-stressed or cold-acclimated leaves. Cold acclimation also resulted in an increase in the reduction state of the stroma, as indicated by an increased total activity and activation state of NADP-dependent malate dehydrogenase, and increased light-dependent activities of the major regulatory enzymes of the oxidative pentose-phosphate pathway. We suggest that the photosynthetic capacity during cold stress as well as cold acclimation is altered by limitations at the level of consumption of reducing power in carbon metabolism.

@article{bailey_acclimation_2001,
	title = {Acclimation of {Arabidopsis} thaliana to the light environment: the existence of separate low light and high light responses},
	volume = {213},
	issn = {1432-2048},
	shorttitle = {Acclimation of {Arabidopsis} thaliana to the light environment},
	url = {https://doi.org/10.1007/s004250100556},
	doi = {10/c3n6p7},
	abstract = {The capacity for photosynthetic acclimation in Arabidopsis thaliana (L.) Heynh. cv. Landsberg erecta was assessed during growth over a broad range of irradiance. Discontinuities in the response to growth irradiance were revealed for the light- and CO2-saturated rate of photosynthesis (Pmax) and the ratio of chlorophyll a to chlorophyll b (Chl a/b). Three separate phases in the response of Pmax and Chl a/b to growth light were evident, with increases at low and high irradiance ranges and a plateau at intermediate irradiance. By measuring all chlorophyll-containing components of the thylakoid membrane that contribute to Chl a/b we reveal that distinct strategies for growth at low and high irradiance underlie the discontinuous response. These strategies include, in addition to changes in the major light-harvesting complexes of photosystem II (LHCII), large shifts in the amounts of both reaction centres as well as significant changes in the levels of minor LHCII and LHCI components.},
	language = {en},
	number = {5},
	urldate = {2021-11-02},
	journal = {Planta},
	author = {Bailey, Shaun and Walters, Robin G. and Jansson, Stefan and Horton, Peter},
	month = sep,
	year = {2001},
	pages = {794--801},
}

The capacity for photosynthetic acclimation in Arabidopsis thaliana (L.) Heynh. cv. Landsberg erecta was assessed during growth over a broad range of irradiance. Discontinuities in the response to growth irradiance were revealed for the light- and CO2-saturated rate of photosynthesis (Pmax) and the ratio of chlorophyll a to chlorophyll b (Chl a/b). Three separate phases in the response of Pmax and Chl a/b to growth light were evident, with increases at low and high irradiance ranges and a plateau at intermediate irradiance. By measuring all chlorophyll-containing components of the thylakoid membrane that contribute to Chl a/b we reveal that distinct strategies for growth at low and high irradiance underlie the discontinuous response. These strategies include, in addition to changes in the major light-harvesting complexes of photosystem II (LHCII), large shifts in the amounts of both reaction centres as well as significant changes in the levels of minor LHCII and LHCI components.

@article{carol_pasticcino1_2001,
	title = {{PASTICCINO1} ({AtFKBP70}) is a nuclear-localised immunophilin required during {Arabidopsis} thaliana embryogenesis},
	volume = {161},
	issn = {0168-9452},
	url = {https://www.sciencedirect.com/science/article/pii/S016894520100437X},
	doi = {10/bwth5k},
	abstract = {The PASTICCINO1 (PAS1) gene of Arabidopsis thaliana encodes a protein with homology to the FK506-binding protein (FKBP) class of immunophilins. To begin to understand more about the possible function of PAS1, we tested some properties of recombinant PAS1 protein and analysed the expression of the gene in Arabidopsis embryos and cell cultures and in tobacco cells. In pas1-1/+ heterozygote embryos the pas1-1 allele is expressed at very low levels in all cells, but it is misexpressed in the pas1-1 homozygote mutant at the same stage. Anti-PAS1 affinity-purified antibodies recognise a 70 kDa protein from dividing cell cultures of Arabidopsis. In indirect immunofluorescence, the same antibodies label the nuclei of dividing tobacco BY-2 cells. In a protease-coupled assay, recombinant PAS1 protein has low peptidylprolyl cis–trans isomerase (PPIase) activity, which is inhibited by the immunosuppressive drugs FK506 and rapamycin, but not by cyclosporin. PAS1 also binds calmodulin in vitro. This data suggests the importance of the correctly regulated production of functional PAS1 protein, a likely nuclear-localised FKBP, for the correct development of the plant embryo.},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Plant Science},
	author = {Carol, Rachel J. and Breiman, Adina and Erel, Noa and Vittorioso, Paola and Bellini, Catherine},
	month = aug,
	year = {2001},
	keywords = {Calmodulin, Embryogenesis, FKBP, Nucleus, PPIase},
	pages = {527--535},
}

The PASTICCINO1 (PAS1) gene of Arabidopsis thaliana encodes a protein with homology to the FK506-binding protein (FKBP) class of immunophilins. To begin to understand more about the possible function of PAS1, we tested some properties of recombinant PAS1 protein and analysed the expression of the gene in Arabidopsis embryos and cell cultures and in tobacco cells. In pas1-1/+ heterozygote embryos the pas1-1 allele is expressed at very low levels in all cells, but it is misexpressed in the pas1-1 homozygote mutant at the same stage. Anti-PAS1 affinity-purified antibodies recognise a 70 kDa protein from dividing cell cultures of Arabidopsis. In indirect immunofluorescence, the same antibodies label the nuclei of dividing tobacco BY-2 cells. In a protease-coupled assay, recombinant PAS1 protein has low peptidylprolyl cis–trans isomerase (PPIase) activity, which is inhibited by the immunosuppressive drugs FK506 and rapamycin, but not by cyclosporin. PAS1 also binds calmodulin in vitro. This data suggests the importance of the correctly regulated production of functional PAS1 protein, a likely nuclear-localised FKBP, for the correct development of the plant embryo.

@article{wei_parental_2001,
	title = {Parental environment effects on cold acclimation and height growth in lodgepole pine seedlings},
	volume = {50},
	abstract = {Lodgepole pine stands from a number of seed sources were established in different commercial forest environments in northern Sweden in the 1970's as part of the introduction effort of this species. Parental environment effects (aftereffects) were studied in progeny from stands originating from two seed sources (Fireside and Toad River, British Columbia), with each seed source grown in six different Swedish environments. The occurrence of aftereffects on cold acclimation (freezing damage and mortality) and height growth of the progeny was investigated in the greenhouse and freezing chamber. One growing season height and cold acclimation differed significantly among stand sites, though the magnitude of the site effect was relatively small. Seedlings were taller at lower elevations, at higher site indexes and in longer growing degree-days environments. With longer growing degree-days freezing damage was significantly lower in the Fireside origin, but not significantly higher in the Toad River origin. Height and resistance to cold damage were positively correlated in the Fireside origin but not in the Toad River origin. The results suggest that after-effects could be manipulated to benefit reforestation by choosing the proper combination of genetic materials and environments for seed production. Aftereffects could also constitute a problem for tree breeding, because the environment in which a seed sample is produced could be confounded with its inherent genetic value.},
	journal = {Silvae Genetica},
	author = {Wei, R.-P and Lindgren, K. and Lindgren, Dag},
	month = jan,
	year = {2001},
	keywords = {⛔ No DOI found},
	pages = {252--257},
}

Lodgepole pine stands from a number of seed sources were established in different commercial forest environments in northern Sweden in the 1970's as part of the introduction effort of this species. Parental environment effects (aftereffects) were studied in progeny from stands originating from two seed sources (Fireside and Toad River, British Columbia), with each seed source grown in six different Swedish environments. The occurrence of aftereffects on cold acclimation (freezing damage and mortality) and height growth of the progeny was investigated in the greenhouse and freezing chamber. One growing season height and cold acclimation differed significantly among stand sites, though the magnitude of the site effect was relatively small. Seedlings were taller at lower elevations, at higher site indexes and in longer growing degree-days environments. With longer growing degree-days freezing damage was significantly lower in the Fireside origin, but not significantly higher in the Toad River origin. Height and resistance to cold damage were positively correlated in the Fireside origin but not in the Toad River origin. The results suggest that after-effects could be manipulated to benefit reforestation by choosing the proper combination of genetic materials and environments for seed production. Aftereffects could also constitute a problem for tree breeding, because the environment in which a seed sample is produced could be confounded with its inherent genetic value.

@article{nilsson_seasonal_2001,
	title = {Seasonal {Changes} in {Phenological} {Traits} and {Cold} {Hardiness} of {F1}-populations from {Plus}-trees of {Pinus} sylvestris and {Pinus} contorta of {Various} {Geographical} {Origins}},
	volume = {16},
	issn = {0282-7581},
	url = {https://doi.org/10.1080/028275801300004361},
	doi = {10/fqq26x},
	abstract = {A 3 yr phenological study of six F1-populations from plus-trees of Scots pine (Pinus sylvestris L.) from 61 to 68° N and five F1-populations from plus-trees of lodgepole pine (Pinus contorta var. latifolia Engelm.) from 55 to 63° N was performed in a Swedish field trial at latitude 64°15' N. Lodgepole pine generally dehardened slightly earlier in spring, and had earlier onset and later cessation of shoot elongation than Scots pine. Early onset and early cessation of shoot elongation were more closely related to a northern latitude of origin in Scots pine than in lodgepole pine. Frost hardiness, needle dry matter proportion, and needle attachment to current year shoots in late summer and autumn were positively related to the latitude of origin in both species. Freeze tests showed that the cold acclimation rhythm of lodgepole pine in the autumn was comparable to that of Scots pine of 5-9° of latitude more northern origin. With respect to timing of dehardening in spring, shoot elongation rhythm (excluding growth cessation), cold acclimation (cold tolerance) in the autumn and winter cold hardiness, lodgepole pine from above 60° N appears phenologically as adapted to the climate of the test site on latitude 64° N as the recommended Scots pine from latitude 66° N. However, later growth cessation, lower dry matter content and needle attachment in the autumn, and possibly a greater tendency to deharden occasionally in late winter indicated poorer adaptation of these northern lodgepole pine populations.},
	number = {1},
	urldate = {2021-11-02},
	journal = {Scandinavian Journal of Forest Research},
	author = {Nilsson, Jan-Erik},
	month = jan,
	year = {2001},
	note = {Publisher: Taylor \& Francis
\_eprint: https://doi.org/10.1080/028275801300004361},
	keywords = {Cold Acclimation, Dehardening, Growing Season, Growth Rhythm, Matter Freeze Test, Needles, Phenology, Shoot Elongation, Winter Hardiness},
	pages = {7--20},
}

A 3 yr phenological study of six F1-populations from plus-trees of Scots pine (Pinus sylvestris L.) from 61 to 68° N and five F1-populations from plus-trees of lodgepole pine (Pinus contorta var. latifolia Engelm.) from 55 to 63° N was performed in a Swedish field trial at latitude 64°15' N. Lodgepole pine generally dehardened slightly earlier in spring, and had earlier onset and later cessation of shoot elongation than Scots pine. Early onset and early cessation of shoot elongation were more closely related to a northern latitude of origin in Scots pine than in lodgepole pine. Frost hardiness, needle dry matter proportion, and needle attachment to current year shoots in late summer and autumn were positively related to the latitude of origin in both species. Freeze tests showed that the cold acclimation rhythm of lodgepole pine in the autumn was comparable to that of Scots pine of 5-9° of latitude more northern origin. With respect to timing of dehardening in spring, shoot elongation rhythm (excluding growth cessation), cold acclimation (cold tolerance) in the autumn and winter cold hardiness, lodgepole pine from above 60° N appears phenologically as adapted to the climate of the test site on latitude 64° N as the recommended Scots pine from latitude 66° N. However, later growth cessation, lower dry matter content and needle attachment in the autumn, and possibly a greater tendency to deharden occasionally in late winter indicated poorer adaptation of these northern lodgepole pine populations.

@article{hertzberg_transcriptional_2001,
	title = {A transcriptional roadmap to wood formation},
	volume = {98},
	copyright = {Copyright © 2001, The National Academy of Sciences},
	issn = {0027-8424, 1091-6490},
	url = {https://www.pnas.org/content/98/25/14732},
	doi = {10/ckrdsz},
	abstract = {The large vascular meristem of poplar trees with its highly organized secondary xylem enables the boundaries between different developmental zones to be easily distinguished. This property of wood-forming tissues allowed us to determine a unique tissue-specific transcript profile for a well defined developmental gradient. RNA was prepared from different developmental stages of xylogenesis for DNA microarray analysis by using a hybrid aspen unigene set consisting of 2,995 expressed sequence tags. The analysis revealed that the genes encoding lignin and cellulose biosynthetic enzymes, as well as a number of transcription factors and other potential regulators of xylogenesis, are under strict developmental stage-specific transcriptional regulation.},
	language = {en},
	number = {25},
	urldate = {2021-11-02},
	journal = {Proceedings of the National Academy of Sciences},
	author = {Hertzberg, Magnus and Aspeborg, Henrik and Schrader, Jarmo and Andersson, Anders and Erlandsson, Rikard and Blomqvist, Kristina and Bhalerao, Rupali and Uhlén, Mathias and Teeri, Tuula T. and Lundeberg, Joakim and Sundberg, Björn and Nilsson, Peter and Sandberg, Göran},
	month = dec,
	year = {2001},
	pmid = {11724959},
	note = {Publisher: National Academy of Sciences
Section: Biological Sciences},
	pages = {14732--14737},
}

The large vascular meristem of poplar trees with its highly organized secondary xylem enables the boundaries between different developmental zones to be easily distinguished. This property of wood-forming tissues allowed us to determine a unique tissue-specific transcript profile for a well defined developmental gradient. RNA was prepared from different developmental stages of xylogenesis for DNA microarray analysis by using a hybrid aspen unigene set consisting of 2,995 expressed sequence tags. The analysis revealed that the genes encoding lignin and cellulose biosynthetic enzymes, as well as a number of transcription factors and other potential regulators of xylogenesis, are under strict developmental stage-specific transcriptional regulation.

@article{schinkel_small_2001,
	title = {A small family of novel {CuZn}-superoxide dismutases with high isoelectric points in hybrid aspen},
	volume = {213},
	issn = {1432-2048},
	url = {https://doi.org/10.1007/s004250000505},
	doi = {10/fbp32g},
	abstract = {Several CuZn-superoxide dismutases (SODs; EC 1.15.1.1) were cloned from hybrid aspen (Populus tremula L. × tremuloides Michx.). Two of the cloned genes encode representatives of a novel type of CuZn-SOD and we named it HipI-SOD because of its high isoelectric point (≥9). The SODs were cloned by screening a cDNA library with a probe based on a Scots pine (Pinus sylvestris L.) CuZn-SOD that is predominantly located extracellularly. The expression pattern of HipI-SOD was examined using a Northern blot technique and compared with the expression patterns of cytosolic and chloroplastic SODs. Distinct expression patterns were observed for the three types of CuZn-SOD, with HipI-SODs showing strong expression in apical tissues. Southern blots as well as protein analysis suggest that these novel HipI-SODs belong to a small gene family, one member of which might be monomeric.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Planta},
	author = {Schinkel, Helga and Hertzberg, Magnus and Wingsle, Gunnar},
	month = jun,
	year = {2001},
	pages = {272--279},
}

Several CuZn-superoxide dismutases (SODs; EC 1.15.1.1) were cloned from hybrid aspen (Populus tremula L. × tremuloides Michx.). Two of the cloned genes encode representatives of a novel type of CuZn-SOD and we named it HipI-SOD because of its high isoelectric point (≥9). The SODs were cloned by screening a cDNA library with a probe based on a Scots pine (Pinus sylvestris L.) CuZn-SOD that is predominantly located extracellularly. The expression pattern of HipI-SOD was examined using a Northern blot technique and compared with the expression patterns of cytosolic and chloroplastic SODs. Distinct expression patterns were observed for the three types of CuZn-SOD, with HipI-SODs showing strong expression in apical tissues. Southern blots as well as protein analysis suggest that these novel HipI-SODs belong to a small gene family, one member of which might be monomeric.

@article{ivanov_photosynthetic_2001,
	title = {Photosynthetic electron transport adjustments in overwintering {Scots} pine ({Pinus} sylvestris {L}.)},
	volume = {213},
	issn = {1432-2048},
	url = {https://doi.org/10.1007/s004250100522},
	doi = {10/dj265j},
	abstract = {As shown before [C. Ottander et al. (1995) Planta 197:176–183], there is a severe inhibition of the photosystem (PS) II photochemical efficiency of Scots pine (Pinus sylvestris L.) during the winter. In contrast, the in vivo PSI photochemistry is less inhibited during winter as shown by in vivo measurements of ΔA820/A820 (P700+). There was also an enhanced cyclic electron transfer around PSI in winter-stressed needles as indicated by 4-fold faster reduction kinetics of P700+. The differential functional stability of PSII and PSI was accompanied by a 3.7-fold higher intersystem electron pool size, and a 5-fold increase in the stromal electron pool available for P700+ reduction. There was also a strong reduction of the QB band in the thermoluminescence glow curve and markedly slower QA– re-oxidation in needles of winter pine, indicating an inhibition of electron transfer between QA and QB. The data presented indicate that the plastoquinone pool is largely reduced in winter pine, and that this reduced state is likely to be of metabolic rather than photochemical origin. The retention of PSI photochemistry, and the suggested metabolic reduction of the plastoquinone pool in winter stressed needles of Scots pine are discussed in terms of the need for enhanced photoprotection of the needles during the winter and the role of metabolically supplied energy for the recovery of photosynthesis from winter stress in evergreens.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Planta},
	author = {Ivanov, A. and Sane, P. and Zeinalov, Y. and Malmberg, G. and Gardeström, P. and Huner, N. and Öquist, G.},
	month = aug,
	year = {2001},
	pages = {575--585},
}

As shown before [C. Ottander et al. (1995) Planta 197:176–183], there is a severe inhibition of the photosystem (PS) II photochemical efficiency of Scots pine (Pinus sylvestris L.) during the winter. In contrast, the in vivo PSI photochemistry is less inhibited during winter as shown by in vivo measurements of ΔA820/A820 (P700+). There was also an enhanced cyclic electron transfer around PSI in winter-stressed needles as indicated by 4-fold faster reduction kinetics of P700+. The differential functional stability of PSII and PSI was accompanied by a 3.7-fold higher intersystem electron pool size, and a 5-fold increase in the stromal electron pool available for P700+ reduction. There was also a strong reduction of the QB band in the thermoluminescence glow curve and markedly slower QA– re-oxidation in needles of winter pine, indicating an inhibition of electron transfer between QA and QB. The data presented indicate that the plastoquinone pool is largely reduced in winter pine, and that this reduced state is likely to be of metabolic rather than photochemical origin. The retention of PSI photochemistry, and the suggested metabolic reduction of the plastoquinone pool in winter stressed needles of Scots pine are discussed in terms of the need for enhanced photoprotection of the needles during the winter and the role of metabolically supplied energy for the recovery of photosynthesis from winter stress in evergreens.

@article{dolusic_biotinylated_2001,
	title = {Biotinylated {Indoles} as {Probes} for {Indole}-{Binding} {Proteins}},
	volume = {12},
	issn = {1043-1802},
	url = {https://doi.org/10.1021/bc000035o},
	doi = {10/dmdv93},
	abstract = {Biotinylated indoles were prepared for application as bifunctional probes for the detection of indole-binding proteins which participate in the life processes of humans, animals, plants, and bacteria. The indole nucleus was functionalized, at ring positions 3, 5, or 6, by attachment of a 2-aminoethyl group, which was then coupled to the carboxyl moiety of biotin, via a spacer composed of 3 or 4 concatenated β-alanine residues. The constructs thus obtained were able to inhibit tryptophanase activity, similarly to indole in a concentration-dependent manner. They also bound strongly to lysozyme and weakly to bovine and human serum albumins, in accordance with the known affinities of these proteins for indole and 3-(2-aminoethyl)indole (tryptamine). The biotin end of the protein-bound bifunctional probes could then be detected by coupling to (strept)avidin conjugated to alkaline phosphatase or horseradish peroxidase, followed by incubation with substrates which are converted by these enzymes to intensely colored or chemiluminescent products.},
	number = {2},
	urldate = {2021-11-02},
	journal = {Bioconjugate Chemistry},
	author = {Dolušić, Eduard and Kowalczyk, Mariusz and Magnus, Volker and Sandberg, Göran and Normanly, Jennifer},
	month = mar,
	year = {2001},
	note = {Publisher: American Chemical Society},
	pages = {152--162},
}

Biotinylated indoles were prepared for application as bifunctional probes for the detection of indole-binding proteins which participate in the life processes of humans, animals, plants, and bacteria. The indole nucleus was functionalized, at ring positions 3, 5, or 6, by attachment of a 2-aminoethyl group, which was then coupled to the carboxyl moiety of biotin, via a spacer composed of 3 or 4 concatenated β-alanine residues. The constructs thus obtained were able to inhibit tryptophanase activity, similarly to indole in a concentration-dependent manner. They also bound strongly to lysozyme and weakly to bovine and human serum albumins, in accordance with the known affinities of these proteins for indole and 3-(2-aminoethyl)indole (tryptamine). The biotin end of the protein-bound bifunctional probes could then be detected by coupling to (strept)avidin conjugated to alkaline phosphatase or horseradish peroxidase, followed by incubation with substrates which are converted by these enzymes to intensely colored or chemiluminescent products.

@article{jackowski_identification_2001,
	title = {Identification of {Lhcb1}/{Lhcb2}/{Lhcb3} heterotrimers of the main light-harvesting chlorophyll a/b–protein complex of {Photosystem} {II} ({LHC} {II})},
	volume = {1504},
	issn = {0005-2728},
	url = {https://www.sciencedirect.com/science/article/pii/S0005272800002620},
	doi = {10/dfzb58},
	abstract = {Using non-denaturing isoelectric focusing in polyacrylamide vertical slab gel, we have purified to homogeneity three trimeric subcomplexes of LHC II from Arabidopsis thylakoid membranes. The polypeptide composition of the subcomplexes were studied by immunoblotting. Our results indicate the existence in vivo of LHC II heterotrimers containing Lhcb1, Lhcb2 and Lhcb3 gene products.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Biochimica et Biophysica Acta (BBA) - Bioenergetics},
	author = {Jackowski, Grzegorz and Kacprzak, Karol and Jansson, Stefan},
	month = apr,
	year = {2001},
	keywords = {(), Light harvesting complex II, Subcomplex, Trimer},
	pages = {340--345},
}

Using non-denaturing isoelectric focusing in polyacrylamide vertical slab gel, we have purified to homogeneity three trimeric subcomplexes of LHC II from Arabidopsis thylakoid membranes. The polypeptide composition of the subcomplexes were studied by immunoblotting. Our results indicate the existence in vivo of LHC II heterotrimers containing Lhcb1, Lhcb2 and Lhcb3 gene products.

@article{ohlund_growth_2001,
	title = {Growth of conifer seedlings on organic and inorganic nitrogen sources},
	volume = {21},
	issn = {0829-318X},
	url = {https://academic.oup.com/treephys/article/21/18/1319/1657768},
	doi = {10/fxqz9k},
	abstract = {Abstract. Effects of organic and inorganic nitrogen sources on growth and mineral nutrient concentrations of Scots pine (Pinus sylvestris L.) and Norway spruce},
	language = {en},
	number = {18},
	urldate = {2021-11-02},
	journal = {Tree Physiology},
	author = {Öhlund, Jonas and Näsholm, Torgny},
	month = dec,
	year = {2001},
	note = {Publisher: Oxford Academic},
	pages = {1319--1326},
}

Abstract. Effects of organic and inorganic nitrogen sources on growth and mineral nutrient concentrations of Scots pine (Pinus sylvestris L.) and Norway spruce

@article{nordin_nitrogen_2001,
	title = {Nitrogen forms in bark, wood and foliage of nitrogen-fertilized {Pinus} sylvestris},
	volume = {21},
	issn = {0829-318X},
	url = {https://doi.org/10.1093/treephys/21.1.59},
	doi = {10/fz2v7x},
	abstract = {Cycling of soluble non-protein N compounds is thought to be indicative of the N-nutritional status of trees. We determined the major N forms in bark, wood and foliage and estimated the dependence of prevalent N forms on N availability in Pinus sylvestris L. trees from northern Sweden. Trees subjected to severe N limitation and trees that had been fertilized with an average 64 kg N ha−1 year−1 for 25 years were analyzed. Bark and wood samples were collected by tangentially cryo-sectioning the trunk into 30-μm thick sections, from the bark to the functional xylem. Soluble amino compounds were extracted from the sections for analysis. Sap samples from twigs were obtained by centrifugation, and bark samples from twigs were obtained by tissue extraction.In both needles and bark, arginine dominated the amino-N pool. Because arginine concentrations in needles increased with N fertilization, arginine dominance of the amino-N pool in needles was higher in N-fertilized trees than in control trees. In bark, N fertilization resulted in a large increase in glutamine concentration, so that glutamine accounted for a larger proportion of the amino-N pool in bark in N-fertilized trees than in control trees. Glutamine dominated the amino-N pool in wood of control trees. Nitrogen fertilization resulted in an increased proportion of arginine in the wood amino-N pool. We conclude that the composition of the amino-N pools in bark, wood and foliage is highly sensitive to N supply. The composition of the amino-N pools can contribute to the regulation of tree N-nutritional status, which is mediated by shoot to root signalling by long-distance transport of amino compounds.},
	number = {1},
	urldate = {2021-11-02},
	journal = {Tree Physiology},
	author = {Nordin, Annika and Uggla, Claes and Näsholm, Torgny},
	month = jan,
	year = {2001},
	pages = {59--64},
}

Cycling of soluble non-protein N compounds is thought to be indicative of the N-nutritional status of trees. We determined the major N forms in bark, wood and foliage and estimated the dependence of prevalent N forms on N availability in Pinus sylvestris L. trees from northern Sweden. Trees subjected to severe N limitation and trees that had been fertilized with an average 64 kg N ha−1 year−1 for 25 years were analyzed. Bark and wood samples were collected by tangentially cryo-sectioning the trunk into 30-μm thick sections, from the bark to the functional xylem. Soluble amino compounds were extracted from the sections for analysis. Sap samples from twigs were obtained by centrifugation, and bark samples from twigs were obtained by tissue extraction.In both needles and bark, arginine dominated the amino-N pool. Because arginine concentrations in needles increased with N fertilization, arginine dominance of the amino-N pool in needles was higher in N-fertilized trees than in control trees. In bark, N fertilization resulted in a large increase in glutamine concentration, so that glutamine accounted for a larger proportion of the amino-N pool in bark in N-fertilized trees than in control trees. Glutamine dominated the amino-N pool in wood of control trees. Nitrogen fertilization resulted in an increased proportion of arginine in the wood amino-N pool. We conclude that the composition of the amino-N pools in bark, wood and foliage is highly sensitive to N supply. The composition of the amino-N pools can contribute to the regulation of tree N-nutritional status, which is mediated by shoot to root signalling by long-distance transport of amino compounds.

@article{kang_prediction_2001,
	title = {Prediction of genetic gain and gene diversity in seed orchard crops under alternative management strategies},
	volume = {103},
	issn = {1432-2242},
	url = {https://doi.org/10.1007/s001220100700},
	doi = {10/frpj5t},
	abstract = {Genetic gain and the gene diversity of seed crops from clonal seed orchards were formulated considering genetic selection, fertility variation and pollen contamination, and compared for five different management strategies. Genetic response was studied as a function of orchard management tactics. Management variables included the proportion of clones left after genetic thinning and/or selective seed harvesting. Formulae were derived to calculate gene diversity (expressed as group coancestry or status number) based on the sex ratio in an orchard population. The influence of having different sets of clones serving as seed parents, or pollen parents, or as both, was analysed. In addition, the impact on genetic gain and the gene diversity of seed crops was studied quantitatively as a function of the quantity and quality of gene flow from outside the orchard. The negative impact of fertility variation among orchard genotypes on the gene diversity of the seed crop was quantified. Numerical examples were given to illustrate the impact of orchard management alternatives on genetic gain and gene diversity. The formulae and results of this study can be used for identifying favourable alternatives for the management of seed orchards.},
	language = {en},
	number = {6},
	urldate = {2021-11-02},
	journal = {Theoretical and Applied Genetics},
	author = {Kang, K. S. and Lindgren, D. and Mullin, T. J.},
	month = nov,
	year = {2001},
	pages = {1099--1107},
}

Genetic gain and the gene diversity of seed crops from clonal seed orchards were formulated considering genetic selection, fertility variation and pollen contamination, and compared for five different management strategies. Genetic response was studied as a function of orchard management tactics. Management variables included the proportion of clones left after genetic thinning and/or selective seed harvesting. Formulae were derived to calculate gene diversity (expressed as group coancestry or status number) based on the sex ratio in an orchard population. The influence of having different sets of clones serving as seed parents, or pollen parents, or as both, was analysed. In addition, the impact on genetic gain and the gene diversity of seed crops was studied quantitatively as a function of the quantity and quality of gene flow from outside the orchard. The negative impact of fertility variation among orchard genotypes on the gene diversity of the seed crop was quantified. Numerical examples were given to illustrate the impact of orchard management alternatives on genetic gain and gene diversity. The formulae and results of this study can be used for identifying favourable alternatives for the management of seed orchards.

@article{haffner_air_2001,
	title = {Air {Pollution} and {Lichen} {Physiology}. {Physiological} {Responses} of {Different} {Lichens} in a {Transplant} {Experiment} {Following} an {SO2}-{Gradient}},
	volume = {131},
	issn = {1573-2932},
	url = {https://doi.org/10.1023/A:1011907530430},
	doi = {10/cgsjkw},
	abstract = {Four lichen species, Parmelia sulcata Taylor, Hypogymnia physodes (L.) Nyl., Cetraria islandica (L.)Ach., and Bryoria fuscescens (Gyelnik) Brodo andHawksworth were exposed during autumn and winter at differentsites of the Erzgebirge (Ore Mountains), the Fichtelgebirge andcontrol sites. All lichens tested became visibly damaged withtime. Thallus bleaching started from the edges and went on tothe centre of the thallus. Sites of facilitated gas exchangelike the soralia of P. sulcata and the pseudocyphelles ofC. islandica became preferentially bleached. The sulfateconcentration increased with exposure time reaching 200\% ofunpolluted controls. In contrast to coniferous trees (e.g. Picea abies), further exposure lead to a reduction in the S-concentration in the lichens, as sulfate and otherintracellular metabolites were leached from the thalli due tomembrane damage. The changes in the K-concentration proved tobe an excellent measure for membrane leakiness; it wascorrelated with time of exposure and with SO2 concentrations at the different sites. Photosynthetic capacityand respiration were also strongly affected. Depending on theSO2-dose, the Bryoria species were unable tophotosynthesize as early as 4–8 weeks after exposure, whereasCetraria and Hypogymnia showed clear reduction intheir ability to photoreduce CO2 within 8–10 weeks ofexposure in the field. Parmelia sulcata was found to bethe most tolerant species. After 3–4 months, photosynthesis wasreduced by only 30\%. The bioindicative value of theseobservations is discussed.},
	language = {en},
	number = {1},
	urldate = {2021-11-02},
	journal = {Water, Air, and Soil Pollution},
	author = {Häffner, Eva and Lomský, Bohumir and Hynek, Vladimir and Hällgren, Jan Erik and Batič, Franc and Pfanz, Hardy},
	month = oct,
	year = {2001},
	pages = {185--201},
}

Four lichen species, Parmelia sulcata Taylor, Hypogymnia physodes (L.) Nyl., Cetraria islandica (L.)Ach., and Bryoria fuscescens (Gyelnik) Brodo andHawksworth were exposed during autumn and winter at differentsites of the Erzgebirge (Ore Mountains), the Fichtelgebirge andcontrol sites. All lichens tested became visibly damaged withtime. Thallus bleaching started from the edges and went on tothe centre of the thallus. Sites of facilitated gas exchangelike the soralia of P. sulcata and the pseudocyphelles ofC. islandica became preferentially bleached. The sulfateconcentration increased with exposure time reaching 200% ofunpolluted controls. In contrast to coniferous trees (e.g. Picea abies), further exposure lead to a reduction in the S-concentration in the lichens, as sulfate and otherintracellular metabolites were leached from the thalli due tomembrane damage. The changes in the K-concentration proved tobe an excellent measure for membrane leakiness; it wascorrelated with time of exposure and with SO2 concentrations at the different sites. Photosynthetic capacityand respiration were also strongly affected. Depending on theSO2-dose, the Bryoria species were unable tophotosynthesize as early as 4–8 weeks after exposure, whereasCetraria and Hypogymnia showed clear reduction intheir ability to photoreduce CO2 within 8–10 weeks ofexposure in the field. Parmelia sulcata was found to bethe most tolerant species. After 3–4 months, photosynthesis wasreduced by only 30%. The bioindicative value of theseobservations is discussed.

@article{harrar_fkbps_2001,
	title = {{FKBPs}: at the crossroads of folding and transduction},
	volume = {6},
	issn = {1360-1385},
	shorttitle = {{FKBPs}},
	url = {https://www.sciencedirect.com/science/article/pii/S1360138501020441},
	doi = {10/c79bct},
	abstract = {FK506-binding proteins (FKBPs) belong to the large family of peptidyl–prolyl cis–trans isomerases, which are known to be involved in many cellular processes, such as cell signalling, protein trafficking and transcription. FKBPs associate into protein complexes, although the involvement and precise role of their foldase activity remain to be elucidated. FKBPs represent a large gene family in plants that is involved in growth and development. Disruption of genes encoding FKBPs in plants and animals has underlined the importance of this family of proteins in the regulation of cell division and differentiation.},
	language = {en},
	number = {9},
	urldate = {2021-11-02},
	journal = {Trends in Plant Science},
	author = {Harrar, Yaël and Bellini, Catherine and Faure, Jean-Denis},
	month = sep,
	year = {2001},
	keywords = {Heat shock protein, Ppiase, calcineurin, calcium channel, cell division and differentiation, immunophilin, pasticcino1, receptors, rotamase, salt stress, steroid and TGFβ},
	pages = {426--431},
}

FK506-binding proteins (FKBPs) belong to the large family of peptidyl–prolyl cis–trans isomerases, which are known to be involved in many cellular processes, such as cell signalling, protein trafficking and transcription. FKBPs associate into protein complexes, although the involvement and precise role of their foldase activity remain to be elucidated. FKBPs represent a large gene family in plants that is involved in growth and development. Disruption of genes encoding FKBPs in plants and animals has underlined the importance of this family of proteins in the regulation of cell division and differentiation.

@article{ingvarsson_restoration_2001,
	title = {Restoration of genetic variation lost – the genetic rescue hypothesis},
	volume = {16},
	issn = {0169-5347},
	url = {https://www.sciencedirect.com/science/article/pii/S0169534700020656},
	doi = {10/bcz33n},
	abstract = {It has been long known that immigrants from surrounding populations might prevent the extinction of small populations, a process known as the ‘rescue effect’. This focuses on the demographic effects of migration through the direct positive influence that immigrants have on abundance of the recipient population. Now, two recent papers have indicated another potentially important way that migration might rescue populations from extinction – replenishing genetic variation and reducing inbreeding depression, or what has been termed ‘genetic rescue’.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Trends in Ecology \& Evolution},
	author = {Ingvarsson, Pär K},
	month = feb,
	year = {2001},
	keywords = {Genetic variation, Heterosis, Inbreeding depression, Migration, Population stucture},
	pages = {62--63},
}

It has been long known that immigrants from surrounding populations might prevent the extinction of small populations, a process known as the ‘rescue effect’. This focuses on the demographic effects of migration through the direct positive influence that immigrants have on abundance of the recipient population. Now, two recent papers have indicated another potentially important way that migration might rescue populations from extinction – replenishing genetic variation and reducing inbreeding depression, or what has been termed ‘genetic rescue’.

@article{wei_optimum_2001,
	title = {Optimum breeding generation interval considering buildup of relatedness},
	volume = {31},
	issn = {0045-5067},
	url = {https://cdnsciencepub.com/doi/10.1139/x00-198},
	doi = {10/b5wgzv},
	number = {4},
	urldate = {2021-11-02},
	journal = {Canadian Journal of Forest Research},
	author = {Wei, R -P and Lindgren, D},
	month = apr,
	year = {2001},
	note = {Publisher: NRC Research Press},
	pages = {722--729},
}

@article{tavares_dnase-resistant_2001,
	title = {{DNase}-{Resistant} {DNA} in the {Extracellular} and {Cell} {Wall}-{Associated} {Fractions} of {Frankia} {Strains} {R43} and {CcI3}},
	volume = {42},
	issn = {1432-0991},
	url = {https://doi.org/10.1007/s002840010198},
	doi = {10/dgzrnw},
	abstract = {DNases were shown to be present in the extracellular fraction of Frankia strains R43 and CcI3. In spite of this, DNA was found in both the extracellular and cell wall fractions of these strains, and it was shown that extracellular DNA was resistant to the DNases secreted into the culture medium of both Frankia strains. Furthermore, Southern blot analysis under high stringency conditions revealed the chromosomal origin of the cell wall-adsorbed DNA (CW-DNA). Mobility gel band shift assays suggested that the extracellular DNA and the CW-DNA are engaged in complexes with other molecules, most likely proteins, which are probably responsible for the enzymatic resistance observed against extracellular DNase activities. In addition, it was shown that lysis of a small proportion of the cells in the exponential growth phase may account for the DNA being released into the supernatant and adsorbed to the cell wall.},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Current Microbiology},
	author = {Tavares, Fernando and Sellstedt, Anita},
	month = mar,
	year = {2001},
	pages = {168--172},
}

DNases were shown to be present in the extracellular fraction of Frankia strains R43 and CcI3. In spite of this, DNA was found in both the extracellular and cell wall fractions of these strains, and it was shown that extracellular DNA was resistant to the DNases secreted into the culture medium of both Frankia strains. Furthermore, Southern blot analysis under high stringency conditions revealed the chromosomal origin of the cell wall-adsorbed DNA (CW-DNA). Mobility gel band shift assays suggested that the extracellular DNA and the CW-DNA are engaged in complexes with other molecules, most likely proteins, which are probably responsible for the enzymatic resistance observed against extracellular DNase activities. In addition, it was shown that lysis of a small proportion of the cells in the exponential growth phase may account for the DNA being released into the supernatant and adsorbed to the cell wall.

@article{wold_recent_2001,
	series = {{PLS} {Methods}},
	title = {Some recent developments in {PLS} modeling},
	volume = {58},
	issn = {0169-7439},
	url = {https://www.sciencedirect.com/science/article/pii/S0169743901001563},
	doi = {10/c33v5t},
	abstract = {The original chemometrics partial least squares (PLS) model with two blocks of variables (X and Y), linearly related to each other, has had several enhancements/extensions since the beginning of 1980. We here discuss multi-block and hierarchical PLS modeling for installing a priori knowledge of the data structure and simplifying the model interpretation, variable selection schemes for PLS with often similar objectives, nonlinear PLS, and prefiltered PLS, orthogonal signal correction (OSC). A very recent development, orthogonalized-PLS (O-PLS) is included as a way to accomplish both OSC, and a simpler interpretation of the PLS model. In this context, we also briefly mention time series, batch, and wavelets variants of PLS. These PLS extensions are illustrated by examples from peptide quantitative structure–activity relationships (QSAR) and multivariate characterization of pulp using NIR.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Chemometrics and Intelligent Laboratory Systems},
	author = {Wold, Svante and Trygg, Johan and Berglund, Anders and Antti, Henrik},
	month = oct,
	year = {2001},
	keywords = {Chemometrics, Orthogonalized-PLS, PLS modeling},
	pages = {131--150},
}

The original chemometrics partial least squares (PLS) model with two blocks of variables (X and Y), linearly related to each other, has had several enhancements/extensions since the beginning of 1980. We here discuss multi-block and hierarchical PLS modeling for installing a priori knowledge of the data structure and simplifying the model interpretation, variable selection schemes for PLS with often similar objectives, nonlinear PLS, and prefiltered PLS, orthogonal signal correction (OSC). A very recent development, orthogonalized-PLS (O-PLS) is included as a way to accomplish both OSC, and a simpler interpretation of the PLS model. In this context, we also briefly mention time series, batch, and wavelets variants of PLS. These PLS extensions are illustrated by examples from peptide quantitative structure–activity relationships (QSAR) and multivariate characterization of pulp using NIR.

@article{wennstrom_early_2001,
	title = {Early seedling growth of {Pinus} sylvestris after sowing with a mixture of stand and orchard seed in dense spacings},
	volume = {31},
	issn = {0045-5067},
	url = {https://cdnsciencepub.com/doi/10.1139/x01-050},
	doi = {10/c85wp7},
	number = {7},
	urldate = {2021-11-02},
	journal = {Canadian Journal of Forest Research},
	author = {Wennström, Ulfstand and Bergsten, Urban and Nilsson, Jan-Erik},
	month = jul,
	year = {2001},
	note = {Publisher: NRC Research Press},
	pages = {1184--1194},
}

@article{persson_amino_2001,
	title = {Amino acid uptake: a widespread ability among boreal forest plants},
	volume = {4},
	issn = {1461-0248},
	shorttitle = {Amino acid uptake},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1461-0248.2001.00260.x},
	doi = {10/b4hp95},
	abstract = {Amino acids constitute a potentially important source of nitrogen for plants in boreal forest ecosystems. Accordingly, it may be suggested that distinct plant species differing abilities to take up amino acids constitutes an important factor in determining plant ecosystem composition. Using GC-MS and isotopically labelled amino acids, we measured the simultaneous uptake of 15 different amino acids by 31 common boreal forest plant species. The results from this study show that all plant species tested, representing a wide variety of plant types, have the ability to take up amino acids from an incubation solution. Furthermore, uptake rates were unrelated to mycorrhizal associations as well as habitat soil amino acid concentrations and plant nitrogen availability dependence as measured by Ellenberg nitrogen indicator values. These results suggest that mycorrhiza is of minor importance for discrete plant amino acid uptake rates and further points out the potential importance of amino acids to plant nitrogen nutrition in boreal forest ecosystems.},
	language = {en},
	number = {5},
	urldate = {2021-11-02},
	journal = {Ecology Letters},
	author = {Persson, Jörgen and Näsholm, Torgny},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1461-0248.2001.00260.x},
	keywords = {Bursa of Fabricius, cellular memory, cost of immunity, parasite–host interaction, prospecting, thymus},
	pages = {434--438},
}

Amino acids constitute a potentially important source of nitrogen for plants in boreal forest ecosystems. Accordingly, it may be suggested that distinct plant species differing abilities to take up amino acids constitutes an important factor in determining plant ecosystem composition. Using GC-MS and isotopically labelled amino acids, we measured the simultaneous uptake of 15 different amino acids by 31 common boreal forest plant species. The results from this study show that all plant species tested, representing a wide variety of plant types, have the ability to take up amino acids from an incubation solution. Furthermore, uptake rates were unrelated to mycorrhizal associations as well as habitat soil amino acid concentrations and plant nitrogen availability dependence as measured by Ellenberg nitrogen indicator values. These results suggest that mycorrhiza is of minor importance for discrete plant amino acid uptake rates and further points out the potential importance of amino acids to plant nitrogen nutrition in boreal forest ecosystems.

@article{grebe_cell_2001,
	title = {Cell axiality and polarity in plants — adding pieces to the puzzle},
	volume = {4},
	issn = {1369-5266},
	url = {https://www.sciencedirect.com/science/article/pii/S1369526600002107},
	doi = {10/dnhwm4},
	abstract = {Plant cell polarity is important for cellular function and multicellular development. Classical physiological and cell biological analyses identified cues that orient cell polarity and suggested molecules that translate a cue into intracellular asymmetry. A range of proteins that either mark or are involved in the establishment of a (polar) axis are now available, as are many relevant mutants. These tools are likely to facilitate a dissection of the molecular mechanisms behind cell and organ polarity in the near future.},
	language = {en},
	number = {6},
	urldate = {2021-11-02},
	journal = {Current Opinion in Plant Biology},
	author = {Grebe, Markus and Xu, Jian and Scheres, Ben},
	month = dec,
	year = {2001},
	keywords = {cell axiality, cell polarity, cytoskeleton, embryo development, pollen tube, tip growth, trichoblasts, trichomes},
	pages = {520--526},
}

Plant cell polarity is important for cellular function and multicellular development. Classical physiological and cell biological analyses identified cues that orient cell polarity and suggested molecules that translate a cue into intracellular asymmetry. A range of proteins that either mark or are involved in the establishment of a (polar) axis are now available, as are many relevant mutants. These tools are likely to facilitate a dissection of the molecular mechanisms behind cell and organ polarity in the near future.

@article{waldmann_effect_2001,
	title = {The effect of inbreeding on fluctuating asymmetry in {Scabiosa} canescens ({Dipsacaceae})},
	volume = {15},
	issn = {1573-8477},
	url = {https://doi.org/10.1023/A:1013866608313},
	doi = {10/cmbck5},
	abstract = {Developmental instability and fluctuating asymmetry (FA) describe the inability of organisms to correct for random accidents under development and has become a major but controversial topic in evolutionary biology. Theoretical models predict that the level of FA should increase as a result of inbreeding, but empirical results are ambiguous. Moreover, the relationship between fitness and FA is still debated. In the current study, plants from a population of Scabiosa canescens, a locally rare species in southern Sweden, were raised under uniform growth conditions to examine the effects of one-generation of selfing and outcrossing on FA in flower morphology. The level of flower FA was significantly higher (p = 0.038) for inbred progeny than for offspring derived from outcross pollinations. Given that earlier studies of this species have found no negative relation between heterozygosity and FA, the results support the conclusion that expression of deleterious recessive alleles are responsible for the increase of FA. There was no correlation between FA and estimates of five fitness-related traits when estimated at the individual level. However, a companion study found significant inbreeding depression for all fitness traits, and a negative association between FA and fitness could therefore be asserted at the treatment level (inbred/outbred progeny). Hence, FA seems to be useful to predict inbreeding depression in S. canescens, but specific individuals with high fitness cannot be identified based on their FA levels.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Evolutionary Ecology},
	author = {Waldmann, Patrik},
	month = mar,
	year = {2001},
	pages = {117--127},
}

Developmental instability and fluctuating asymmetry (FA) describe the inability of organisms to correct for random accidents under development and has become a major but controversial topic in evolutionary biology. Theoretical models predict that the level of FA should increase as a result of inbreeding, but empirical results are ambiguous. Moreover, the relationship between fitness and FA is still debated. In the current study, plants from a population of Scabiosa canescens, a locally rare species in southern Sweden, were raised under uniform growth conditions to examine the effects of one-generation of selfing and outcrossing on FA in flower morphology. The level of flower FA was significantly higher (p = 0.038) for inbred progeny than for offspring derived from outcross pollinations. Given that earlier studies of this species have found no negative relation between heterozygosity and FA, the results support the conclusion that expression of deleterious recessive alleles are responsible for the increase of FA. There was no correlation between FA and estimates of five fitness-related traits when estimated at the individual level. However, a companion study found significant inbreeding depression for all fitness traits, and a negative association between FA and fitness could therefore be asserted at the treatment level (inbred/outbred progeny). Hence, FA seems to be useful to predict inbreeding depression in S. canescens, but specific individuals with high fitness cannot be identified based on their FA levels.

@article{lerceteau_detection_2001,
	title = {Detection of quantitative trait loci in {Pinus} sylvestris {L}. across years},
	volume = {121},
	issn = {1573-5060},
	url = {https://doi.org/10.1023/A:1012076825293},
	doi = {10/cpbzsf},
	abstract = {In an earlier study, we reported the characterisation of quantitative trait loci (QTLs) for economically important traits related to wood production for a specific year of measurement. However, validating the detected QTLs across years is important for any strategy for marker-assisted selection (MAS). Therefore, we evaluated the consistency of the QTLs across four years in 9 to 12 year-old trees. Data related to tree height were analysed in two ways. The total height was used to characterise QTLs likely to be useful in MAS, and the increment values to evaluate growth regulation. Among the 11 QTLs detected, 4 were found in both the 1996 and 1997 evaluations. QTL numbers and locations related to total height were found to be highly stable. However, the QTL effects progressively changed in successive years, following either an increasing, decreasing or curvilinear trend. Depending on their specific trends, some QTLs may not be expressed at all later in maturity, or they may be expressed at a higher level. This will have direct consequences on the applicability of molecular markers in early screening programs, since a study at the mature stage may also be required. More variation in QTL number and effect was observed relating to height increment than to total height, indicating significant differences in gene expression during the growth periods involved.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Euphytica},
	author = {Lerceteau, Estelle and Szmidt, Alfred E. and Andersson, Bengt},
	month = sep,
	year = {2001},
	pages = {117--122},
}

In an earlier study, we reported the characterisation of quantitative trait loci (QTLs) for economically important traits related to wood production for a specific year of measurement. However, validating the detected QTLs across years is important for any strategy for marker-assisted selection (MAS). Therefore, we evaluated the consistency of the QTLs across four years in 9 to 12 year-old trees. Data related to tree height were analysed in two ways. The total height was used to characterise QTLs likely to be useful in MAS, and the increment values to evaluate growth regulation. Among the 11 QTLs detected, 4 were found in both the 1996 and 1997 evaluations. QTL numbers and locations related to total height were found to be highly stable. However, the QTL effects progressively changed in successive years, following either an increasing, decreasing or curvilinear trend. Depending on their specific trends, some QTLs may not be expressed at all later in maturity, or they may be expressed at a higher level. This will have direct consequences on the applicability of molecular markers in early screening programs, since a study at the mature stage may also be required. More variation in QTL number and effect was observed relating to height increment than to total height, indicating significant differences in gene expression during the growth periods involved.

@article{funk_d1_2001,
	title = {D1′ centers are less efficient than normal photosystem {II} centers},
	volume = {505},
	issn = {0014-5793},
	url = {https://www.sciencedirect.com/science/article/pii/S0014579301027946},
	doi = {10/b78cc6},
	abstract = {One prominent difference between the photosystem II (PSII) reaction center protein D1′ in Synechocystis 6803 and normal D1 is the replacement of Phe-186 in D1 with leucine in D1′. Mutants of Synechocystis 6803 producing only D1′, or containing engineered D1 proteins with Phe-186 substitutions, were analyzed by 77 K fluorescence emission spectra, chlorophyll a fluorescence induction yield and decay kinetics, and flash-induced oxygen evolution. Compared to D1-containing PSII centers, D1′ centers exhibited a 50\% reduction in variable chlorophyll a fluorescence yield, while the flash-induced O2 evolution pattern was unaffected. In the F186 mutants, both the P680+/QA− recombination and O2 oscillation pattern were noticeably perturbed.},
	language = {en},
	number = {1},
	urldate = {2021-11-02},
	journal = {FEBS Letters},
	author = {Funk, Christiane and Wiklund, Ronney and Schröder, Wolfgang P. and Jansson, Christer},
	month = sep,
	year = {2001},
	keywords = {D1, D1′, Photosystem II},
	pages = {113--117},
}

One prominent difference between the photosystem II (PSII) reaction center protein D1′ in Synechocystis 6803 and normal D1 is the replacement of Phe-186 in D1 with leucine in D1′. Mutants of Synechocystis 6803 producing only D1′, or containing engineered D1 proteins with Phe-186 substitutions, were analyzed by 77 K fluorescence emission spectra, chlorophyll a fluorescence induction yield and decay kinetics, and flash-induced oxygen evolution. Compared to D1-containing PSII centers, D1′ centers exhibited a 50% reduction in variable chlorophyll a fluorescence yield, while the flash-induced O2 evolution pattern was unaffected. In the F186 mutants, both the P680+/QA− recombination and O2 oscillation pattern were noticeably perturbed.

@article{otterhag_n-terminal_2001,
	title = {N-terminal {EF}-hand-like domain is required for phosphoinositide-specific phospholipase {C} activity in {Arabidopsis} thaliana},
	volume = {497},
	copyright = {FEBS Letters 497 (2001) 1873-3468 © 2015 Federation of European Biochemical Societies},
	issn = {1873-3468},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1016/S0014-5793%2801%2902453-X},
	doi = {10/dv4dn5},
	abstract = {Phosphoinositide-specific phospholipase C's (PI-PLCs) are ubiquitous in eukaryotes, from plants to animals, and catalyze the hydrolysis of phosphatidylinositol 4,5-bisphosphate into the two second messengers inositol 1,4,5-trisphosphate and diacylglycerol. In animals, four distinct subfamilies of PI-PLCs have been identified, and the three-dimensional structure of one rat isozyme, PLC-δ1, determined. Plants appear to contain only one gene family encoding PI-PLCs. The catalytic properties of plant PI-PLCs are very similar to those of animal enzymes. However, very little is known about the regulation of plant PI-PLCs. All plant PI-PLCs comprise three domains, X, Y and C2, which are also conserved in isoforms from animals and yeast. We here show that one PI-PLC isozyme from Arabidopsis thaliana, AtPLC2, is predominantly localized in the plasma membrane, and that the conserved N-terminal domain may represent an EF-hand domain that is required for catalytic activity but not for lipid binding.},
	language = {en},
	number = {2-3},
	urldate = {2021-11-02},
	journal = {FEBS Letters},
	author = {Otterhag, Lotta and Sommarin, Marianne and Pical, Christophe},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1016/S0014-5793\%2801\%2902453-X},
	keywords = {5)P2, 5-bisphosphate, Arabidopsis thaliana, EF-hand, PH, PI-PLC, Phosphoinositide, Phosphoinositide-specific phospholipase C, Plasma membrane, PtdIns, PtdIns(4, phosphatidylinositol, phosphatidylinositol 4, phosphoinositide-specific phospholipase C, pleckstrin homology},
	pages = {165--170},
}

Phosphoinositide-specific phospholipase C's (PI-PLCs) are ubiquitous in eukaryotes, from plants to animals, and catalyze the hydrolysis of phosphatidylinositol 4,5-bisphosphate into the two second messengers inositol 1,4,5-trisphosphate and diacylglycerol. In animals, four distinct subfamilies of PI-PLCs have been identified, and the three-dimensional structure of one rat isozyme, PLC-δ1, determined. Plants appear to contain only one gene family encoding PI-PLCs. The catalytic properties of plant PI-PLCs are very similar to those of animal enzymes. However, very little is known about the regulation of plant PI-PLCs. All plant PI-PLCs comprise three domains, X, Y and C2, which are also conserved in isoforms from animals and yeast. We here show that one PI-PLC isozyme from Arabidopsis thaliana, AtPLC2, is predominantly localized in the plasma membrane, and that the conserved N-terminal domain may represent an EF-hand domain that is required for catalytic activity but not for lipid binding.

@article{strengbom_slow_2001,
	title = {Slow recovery of boreal forest ecosystem following decreased nitrogen input},
	volume = {15},
	issn = {1365-2435},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.0269-8463.2001.00538.x},
	doi = {10/dnx7bp},
	abstract = {1 Ecosystem recovery after decreased input of nitrogen was examined in two different fertilization experiments where the fertilization had been terminated for 9 and 47 years, respectively. 2 The species composition of the understorey vegetation showed no signs of recovery 9 years after the fertilization was terminated. Increased sporocarp production of mycorrhizal fungi was seen on formerly fertilized plots compared with plots still receiving N, but the species composition showed large differences compared to control plots. 3 In the second experiment, examined 47 years after termination of fertilization, N favoured bryophytes such as Brachythecium reflexum (Starke) Schimp., Plagiothecium denticulatum (Hedw.) Schimp. and the leaf-parasitic fungus Valdensia heterodoxa Peyronel (attacking Vaccinium myrtillus L.) was more abundant in the formerly N-treated plots than in controls. The abundance of Hylocomium splendens (Hedw.) Schimp., the most common bryophyte under normal N conditions, showed a contrasting pattern, with less abundance in the formerly N-treated plots than in controls. Sporocarp production of N-sensitive mycorrhizal fungi was lower in the formerly N-treated plots. No difference in plant species composition was noticed for vascular plants. 4 These results contrast with other studies that have interpreted reduced N leakage and nutrient levels in trees after decreased N input as a rapid ecosystem recovery. The present study suggests that the time needed for recovery of the ecosystem biota may be substantial in originally N-limited ecosystems.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Functional Ecology},
	author = {Strengbom, J. and Nordin, A. and Näsholm, T. and Ericson, L.},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.0269-8463.2001.00538.x},
	keywords = {Critical load, mycorrhizal fungi, vegetational composition},
	pages = {451--457},
}

1 Ecosystem recovery after decreased input of nitrogen was examined in two different fertilization experiments where the fertilization had been terminated for 9 and 47 years, respectively. 2 The species composition of the understorey vegetation showed no signs of recovery 9 years after the fertilization was terminated. Increased sporocarp production of mycorrhizal fungi was seen on formerly fertilized plots compared with plots still receiving N, but the species composition showed large differences compared to control plots. 3 In the second experiment, examined 47 years after termination of fertilization, N favoured bryophytes such as Brachythecium reflexum (Starke) Schimp., Plagiothecium denticulatum (Hedw.) Schimp. and the leaf-parasitic fungus Valdensia heterodoxa Peyronel (attacking Vaccinium myrtillus L.) was more abundant in the formerly N-treated plots than in controls. The abundance of Hylocomium splendens (Hedw.) Schimp., the most common bryophyte under normal N conditions, showed a contrasting pattern, with less abundance in the formerly N-treated plots than in controls. Sporocarp production of N-sensitive mycorrhizal fungi was lower in the formerly N-treated plots. No difference in plant species composition was noticed for vascular plants. 4 These results contrast with other studies that have interpreted reduced N leakage and nutrient levels in trees after decreased N input as a rapid ecosystem recovery. The present study suggests that the time needed for recovery of the ecosystem biota may be substantial in originally N-limited ecosystems.

@article{witzell_formation_2001,
	title = {Formation and growth of stem cankers caused by {Gremmeniella} abietina on young {Pinus} contorta},
	volume = {31},
	issn = {1439-0329},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1439-0329.2001.00231.x},
	doi = {10/d9wpws},
	abstract = {From 1990 to 1995, the formation and growth of stem cankers caused by Gremmeniella abietina on Pinus contorta var. latifolia was studied in three stands in northern Sweden. The stands were planted in 1976–80. The total number of cankers on 756 trees that were individually followed increased from 233 to 477 during the 5-year period. With 42.0\% of the cankers, the pathogen entered through or from the base of diseased branches, and 33.6\% through visually undamaged bark. Most of the cankers were within 100 cm of the ground. In one of the three areas, the cankers were evenly distributed within 180 cm of the ground. The frequency of cankers facing north exceeded those facing south. The average vertical length of cankers had increased, 55.6\% of cankers had increased their percentage coverage of the stem girth; 13.8\% had fully girdled the stem. At two of the sites, there was a negative correlation between canker coverage of the stem circumference and tree height increment.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Forest Pathology},
	author = {{Witzell}},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1439-0329.2001.00231.x},
	pages = {115--127},
}

From 1990 to 1995, the formation and growth of stem cankers caused by Gremmeniella abietina on Pinus contorta var. latifolia was studied in three stands in northern Sweden. The stands were planted in 1976–80. The total number of cankers on 756 trees that were individually followed increased from 233 to 477 during the 5-year period. With 42.0% of the cankers, the pathogen entered through or from the base of diseased branches, and 33.6% through visually undamaged bark. Most of the cankers were within 100 cm of the ground. In one of the three areas, the cankers were evenly distributed within 180 cm of the ground. The frequency of cankers facing north exceeded those facing south. The average vertical length of cankers had increased, 55.6% of cankers had increased their percentage coverage of the stem girth; 13.8% had fully girdled the stem. At two of the sites, there was a negative correlation between canker coverage of the stem circumference and tree height increment.

@article{waldmann_additive_2001,
	title = {Additive and non-additive genetic architecture of two different-sized populations of {Scabiosa} canescens},
	volume = {86},
	copyright = {2001 The Genetical Society of Great Britain},
	issn = {1365-2540},
	url = {https://www.nature.com/articles/6888730},
	doi = {10/bwf2zr},
	abstract = {Future adaptation to changes in the environment depends on the existence of additive genetic variances within populations. Recently, considerable attention has also been given to the non-additive component, which plays an important role in inbreeding depression and bottleneck situations. In this study, I used data from a North Carolina II crossing experiment, analysed with restricted maximum-likelihood methods, to estimate the additive and dominance genetic (co)variances for eight quantitative characters in two different-sized populations of Scabiosa canescens, a rare and threatened plant in Sweden. There was no evidence for genetic erosion in the small Hällestad population (≈25 individuals) relative to the large Åhus population (≈5000 individuals). In fact, slightly higher heritabilities were found in the Hällestad population. The additive genetic variance was statistically significant for all traits in both populations, but only a few additive covariances reached significance. The Hällestad population also had higher mean levels and more traits with significant dominance variance than the Åhus population. The variance attributable to maternal effects was too low to be considered significant. There was only a weak correspondence between heritabilities for each trait in the present study and previous estimates based on open-pollinated families of the same populations, but the mean heritability (over characters) was consistent between the studies.},
	language = {en},
	number = {6},
	urldate = {2021-11-02},
	journal = {Heredity},
	author = {Waldmann, Patrik},
	month = jun,
	year = {2001},
	note = {Bandiera\_abtest: a
Cg\_type: Nature Research Journals
Number: 6
Primary\_atype: Research
Publisher: Nature Publishing Group},
	keywords = {Biomedicine, Cytogenetics, Ecology, Evolutionary Biology, Human Genetics, Plant Genetics and Genomics, general},
	pages = {648--657},
}

Future adaptation to changes in the environment depends on the existence of additive genetic variances within populations. Recently, considerable attention has also been given to the non-additive component, which plays an important role in inbreeding depression and bottleneck situations. In this study, I used data from a North Carolina II crossing experiment, analysed with restricted maximum-likelihood methods, to estimate the additive and dominance genetic (co)variances for eight quantitative characters in two different-sized populations of Scabiosa canescens, a rare and threatened plant in Sweden. There was no evidence for genetic erosion in the small Hällestad population (≈25 individuals) relative to the large Åhus population (≈5000 individuals). In fact, slightly higher heritabilities were found in the Hällestad population. The additive genetic variance was statistically significant for all traits in both populations, but only a few additive covariances reached significance. The Hällestad population also had higher mean levels and more traits with significant dominance variance than the Åhus population. The variance attributable to maternal effects was too low to be considered significant. There was only a weak correspondence between heritabilities for each trait in the present study and previous estimates based on open-pollinated families of the same populations, but the mean heritability (over characters) was consistent between the studies.

@article{king_gibberellins_2001,
	title = {Gibberellins {Are} {Not} {Required} for {Normal} {Stem} {Growth} in {Arabidopsis} thaliana in the {Absence} of {GAI} and {RGA}},
	volume = {159},
	issn = {1943-2631},
	url = {https://doi.org/10.1093/genetics/159.2.767},
	doi = {10/gn2mhv},
	abstract = {The growth of Arabidopsis thaliana is quantitatively regulated by the phytohormone gibberellin (GA) via two closely related nuclear GA-signaling components, GAI and RGA. Here we test the hypothesis that GAI and RGA function as “GA-derepressible repressors” of plant growth. One prediction of this hypothesis is that plants lacking GAI and RGA do not require GA for normal stem growth. Analysis of GA-deficient mutants lacking GAI and RGA confirms this prediction and suggests that in the absence of GAI and RGA, “growth” rather than “no growth” is the default state of plant stems. The function of the GA-signaling system is thus to act as a control system regulating the amount of this growth. We also demonstrate that the GA dose dependency of hypocotyl elongation is altered in mutants lacking GAI and RGA and propose that increments in GAI/RGA repressor function can explain the quantitative nature of GA responses.},
	number = {2},
	urldate = {2021-11-02},
	journal = {Genetics},
	author = {King, Kathryn E and Moritz, Thomas and Harberd, Nicholas P},
	month = oct,
	year = {2001},
	pages = {767--776},
}

The growth of Arabidopsis thaliana is quantitatively regulated by the phytohormone gibberellin (GA) via two closely related nuclear GA-signaling components, GAI and RGA. Here we test the hypothesis that GAI and RGA function as “GA-derepressible repressors” of plant growth. One prediction of this hypothesis is that plants lacking GAI and RGA do not require GA for normal stem growth. Analysis of GA-deficient mutants lacking GAI and RGA confirms this prediction and suggests that in the absence of GAI and RGA, “growth” rather than “no growth” is the default state of plant stems. The function of the GA-signaling system is thus to act as a control system regulating the amount of this growth. We also demonstrate that the GA dose dependency of hypocotyl elongation is altered in mutants lacking GAI and RGA and propose that increments in GAI/RGA repressor function can explain the quantitative nature of GA responses.

@article{tantikanjana_control_2001,
	title = {Control of axillary bud initiation and shoot architecture in {Arabidopsis} through the {SUPERSHOOT} gene},
	volume = {15},
	issn = {0890-9369, 1549-5477},
	url = {http://genesdev.cshlp.org/content/15/12/1577},
	doi = {10/b2rhkq},
	abstract = {The aerial architecture of flowering plants is determined to a large extent by shoot growth and shoot branching arising from the initiation and growth of axillary meristems. We have identified anArabidopsis mutant, supershoot (sps), which is characterized by a massive overproliferation of shoots, such that a single plant can generate 500 or more inflorescences. Analysis of the mutant plants shows that the primary defect is because of an increase in the number of meristems formed in leaf axils, together with release of bud arrest, resulting in reiterative branch formation from rosette and cauline leaves. The SPS gene is shown here to encode a cytochrome P450, and together with a 3- to 9-fold increase in levels of Z-type cytokinins in sps mutant plants, indicate a role forSPS in modulating hormone levels. The expression pattern ofSPS, with strong expression at the leaf axils, correlates well with the phenotypic defects. Our results indicate that control of shoot branching in Arabidopsis may be accomplished in part by suppression of axillary meristem initiation and growth through the localized attenuation of cytokinin levels at sites of bud initiation.},
	language = {en},
	number = {12},
	urldate = {2021-11-02},
	journal = {Genes \& Development},
	author = {Tantikanjana, Titima and Yong, Jean W. H. and Letham, D. Stuart and Griffith, Megan and Hussain, Mumtaz and Ljung, Karin and Sandberg, Göran and Sundaresan, Venkatesan},
	month = jun,
	year = {2001},
	pmid = {11410537},
	note = {Company: Cold Spring Harbor Laboratory Press
Distributor: Cold Spring Harbor Laboratory Press
Institution: Cold Spring Harbor Laboratory Press
Label: Cold Spring Harbor Laboratory Press
Publisher: Cold Spring Harbor Lab},
	keywords = {Arabidopsis, Axillary meristem, apical dominance, branching, bud initiation, cytochrome P450, cytokinins},
	pages = {1577--1588},
}

The aerial architecture of flowering plants is determined to a large extent by shoot growth and shoot branching arising from the initiation and growth of axillary meristems. We have identified anArabidopsis mutant, supershoot (sps), which is characterized by a massive overproliferation of shoots, such that a single plant can generate 500 or more inflorescences. Analysis of the mutant plants shows that the primary defect is because of an increase in the number of meristems formed in leaf axils, together with release of bud arrest, resulting in reiterative branch formation from rosette and cauline leaves. The SPS gene is shown here to encode a cytochrome P450, and together with a 3- to 9-fold increase in levels of Z-type cytokinins in sps mutant plants, indicate a role forSPS in modulating hormone levels. The expression pattern ofSPS, with strong expression at the leaf axils, correlates well with the phenotypic defects. Our results indicate that control of shoot branching in Arabidopsis may be accomplished in part by suppression of axillary meristem initiation and growth through the localized attenuation of cytokinin levels at sites of bud initiation.

@article{heese_functional_2001,
	title = {Functional characterization of the {KNOLLE}-interacting t-{SNARE} {AtSNAP33} and its role in plant cytokinesis},
	volume = {155},
	issn = {0021-9525},
	url = {https://doi.org/10.1083/jcb.200107126},
	doi = {10/d5kzqn},
	abstract = {Cytokinesis requires membrane fusion during cleavage-furrow ingression in animals and cell plate formation in plants. In Arabidopsis, the Sec1 homologue KEULE (KEU) and the cytokinesis-specific syntaxin KNOLLE (KN) cooperate to promote vesicle fusion in the cell division plane. Here, we characterize AtSNAP33, an Arabidopsis homologue of the t-SNARE SNAP25, that was identified as a KN interactor in a yeast two-hybrid screen. AtSNAP33 is a ubiquitously expressed membrane-associated protein that accumulated at the plasma membrane and during cell division colocalized with KN at the forming cell plate. A T-DNA insertion in the AtSNAP33 gene caused loss of AtSNAP33 function, resulting in a lethal dwarf phenotype. atsnap33 plantlets gradually developed large necrotic lesions on cotyledons and rosette leaves, resembling pathogen-induced cellular responses, and eventually died before flowering. In addition, mutant seedlings displayed cytokinetic defects, and atsnap33 in combination with the cytokinesis mutant keu was embryo lethal. Analysis of the Arabidopsis genome revealed two further SNAP25-like proteins that also interacted with KN in the yeast two-hybrid assay. Our results suggest that AtSNAP33, the first SNAP25 homologue characterized in plants, is involved in diverse membrane fusion processes, including cell plate formation, and that AtSNAP33 function in cytokinesis may be replaced partially by other SNAP25 homologues.},
	number = {2},
	urldate = {2021-11-02},
	journal = {Journal of Cell Biology},
	author = {Heese, Maren and Gansel, Xavier and Sticher, Liliane and Wick, Peter and Grebe, Markus and Granier, Fabienne and Jürgens, Gerd},
	month = oct,
	year = {2001},
	pages = {239--250},
}

Cytokinesis requires membrane fusion during cleavage-furrow ingression in animals and cell plate formation in plants. In Arabidopsis, the Sec1 homologue KEULE (KEU) and the cytokinesis-specific syntaxin KNOLLE (KN) cooperate to promote vesicle fusion in the cell division plane. Here, we characterize AtSNAP33, an Arabidopsis homologue of the t-SNARE SNAP25, that was identified as a KN interactor in a yeast two-hybrid screen. AtSNAP33 is a ubiquitously expressed membrane-associated protein that accumulated at the plasma membrane and during cell division colocalized with KN at the forming cell plate. A T-DNA insertion in the AtSNAP33 gene caused loss of AtSNAP33 function, resulting in a lethal dwarf phenotype. atsnap33 plantlets gradually developed large necrotic lesions on cotyledons and rosette leaves, resembling pathogen-induced cellular responses, and eventually died before flowering. In addition, mutant seedlings displayed cytokinetic defects, and atsnap33 in combination with the cytokinesis mutant keu was embryo lethal. Analysis of the Arabidopsis genome revealed two further SNAP25-like proteins that also interacted with KN in the yeast two-hybrid assay. Our results suggest that AtSNAP33, the first SNAP25 homologue characterized in plants, is involved in diverse membrane fusion processes, including cell plate formation, and that AtSNAP33 function in cytokinesis may be replaced partially by other SNAP25 homologues.

@article{jackson_identification_2001,
	title = {Identification and {Biochemical} {Characterization} of {anArabidopsis} {Indole}-3-acetic {Acid} {Glucosyltransferase}*},
	volume = {276},
	issn = {0021-9258},
	url = {https://www.sciencedirect.com/science/article/pii/S0021925818464423},
	doi = {10/d3cc4r},
	abstract = {Biochemical characterization of recombinant gene products following a phylogenetic analysis of the UDP-glucosyltransferase (UGT) multigene family ofArabidopsis has identified one enzyme (UGT84B1) with high activity toward the plant hormone indole-3-acetic acid (IAA) and three related enzymes (UGT84B2, UGT75B1, and UGT75B2) with trace activities. The identity of the IAA conjugate has been confirmed to be 1-O-indole acetyl glucose ester. A sequence annotated as a UDP-glucose:IAA glucosyltransferase (IAA-UGT) in theArabidopsis genome and expressed sequence tag data bases given its similarity to the maize iaglu gene sequence showed no activity toward IAA. This study describes the first biochemical analysis of a recombinant IAA-UGT and provides the foundation for future genetic approaches to understand the role of 1-O-indole acetyl glucose ester inArabidopsis.},
	language = {en},
	number = {6},
	urldate = {2021-11-02},
	journal = {Journal of Biological Chemistry},
	author = {Jackson, Rosamond G. and Lim, Eng-Kiat and Li, Yi and Kowalczyk, Mariusz and Sandberg, Göran and Hoggett, Jim and Ashford, David A. and Bowles, Dianna J.},
	month = feb,
	year = {2001},
	pages = {4350--4356},
}

Biochemical characterization of recombinant gene products following a phylogenetic analysis of the UDP-glucosyltransferase (UGT) multigene family ofArabidopsis has identified one enzyme (UGT84B1) with high activity toward the plant hormone indole-3-acetic acid (IAA) and three related enzymes (UGT84B2, UGT75B1, and UGT75B2) with trace activities. The identity of the IAA conjugate has been confirmed to be 1-O-indole acetyl glucose ester. A sequence annotated as a UDP-glucose:IAA glucosyltransferase (IAA-UGT) in theArabidopsis genome and expressed sequence tag data bases given its similarity to the maize iaglu gene sequence showed no activity toward IAA. This study describes the first biochemical analysis of a recombinant IAA-UGT and provides the foundation for future genetic approaches to understand the role of 1-O-indole acetyl glucose ester inArabidopsis.

@article{igamberdiev_photorespiratory_2001,
	title = {Photorespiratory flux and mitochondrial contribution to energy and redox balance of barley leaf protoplasts in the light and during light-dark transitions},
	volume = {158},
	issn = {0176-1617},
	url = {https://www.sciencedirect.com/science/article/pii/S0176161704701637},
	doi = {10/fw3mnj},
	abstract = {The contribution of mitochondrial oxidation of photorespiratory and respiratory substrates to subcellular energy and redox balance was investigated in leaf protoplasts of barley (Hordeum vulgare L.). The ATP/ADP ratios (indicating the energy balance) in chloroplasts and in the extrachloroplast compartment were highest in the light in limiting CO2 (photorespiratory conditions), and they drastically increased after illumination if plants were pre-incubated in darkness for 24 hours. After illumination, the ATP/ADP ratio rapidly decreased in chloroplasts. The NADPH/NADP ratio (as an indicator of redox balance) in chloroplasts declined rapidly during the first seconds of darkness, then slowly increased. In limiting CO2, the ratio decreased more slowly during the first minute of darkness corresponding to post-illumination respiratory burst (PIB). During this period, the activation state of chloroplast NADP-malate dehydrogenase was higher in limiting CO2 than in saturating CO2. However, during the light-enhanced dark respiration (LEDR) period, following PIB, there were no differences in subcellular NADPH/NADP ratios in saturating and limiting CO2. A decline in malate and citrate concentrations in protoplasts and activation of mitochondrial NAD-malic enzyme were revealed during LEDR. The results presented highlight the importance of glycine oxidation in mitochondria in energization of the cytosol and chloroplasts and in maintaining redox balance in the light and during the first minute after illumination. And further, they show non-photorespiratory origin of LEDR.},
	language = {en},
	number = {10},
	urldate = {2021-11-02},
	journal = {Journal of Plant Physiology},
	author = {Igamberdiev, Abir U. and Romanowska, Elżbieta and Gardeström, P. e. r.},
	month = jan,
	year = {2001},
	keywords = {light enhanced dark respiration, light-dark transition, mitochondria, photorespiration, post-illumination burst},
	pages = {1325--1332},
}

The contribution of mitochondrial oxidation of photorespiratory and respiratory substrates to subcellular energy and redox balance was investigated in leaf protoplasts of barley (Hordeum vulgare L.). The ATP/ADP ratios (indicating the energy balance) in chloroplasts and in the extrachloroplast compartment were highest in the light in limiting CO2 (photorespiratory conditions), and they drastically increased after illumination if plants were pre-incubated in darkness for 24 hours. After illumination, the ATP/ADP ratio rapidly decreased in chloroplasts. The NADPH/NADP ratio (as an indicator of redox balance) in chloroplasts declined rapidly during the first seconds of darkness, then slowly increased. In limiting CO2, the ratio decreased more slowly during the first minute of darkness corresponding to post-illumination respiratory burst (PIB). During this period, the activation state of chloroplast NADP-malate dehydrogenase was higher in limiting CO2 than in saturating CO2. However, during the light-enhanced dark respiration (LEDR) period, following PIB, there were no differences in subcellular NADPH/NADP ratios in saturating and limiting CO2. A decline in malate and citrate concentrations in protoplasts and activation of mitochondrial NAD-malic enzyme were revealed during LEDR. The results presented highlight the importance of glycine oxidation in mitochondria in energization of the cytosol and chloroplasts and in maintaining redox balance in the light and during the first minute after illumination. And further, they show non-photorespiratory origin of LEDR.

@article{parry_quick_2001,
	title = {Quick on the {Uptake}: {Characterization} of a {Family} of {Plant} {Auxin} {Influx} {Carriers}},
	volume = {20},
	issn = {1435-8107},
	shorttitle = {Quick on the {Uptake}},
	url = {https://doi.org/10.1007/s003440010030},
	doi = {10/drws4q},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Journal of Plant Growth Regulation},
	author = {Parry, Geraint and Marchant, Alan and May, Sean and Swarup, Ranjan and Swarup, Kamal and James, Nick and Graham, Neil and Allen, Trudie and Martucci, Tony and Yemm, Antony and Napier, Richard and Manning, Ken and King, Graham and Bennett, Malcolm},
	month = sep,
	year = {2001},
	pages = {217--225},
}

@article{hauksson_nmr_2001,
	title = {{NMR} processing techniques based on multivariate data analysis and orthogonal signal correction. {13C} {CP}/{MAS} {NMR} spectroscopic characterization of softwood kraft pulp},
	volume = {39},
	issn = {1097-458X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/mrc.838},
	doi = {10/cj6rtd},
	abstract = {This paper presents a novel way of extracting information from a series of severely overlapped NMR spectra using multivariate data analysis techniques. A number of softwood pulps were prepared from wood chips that were subjected to kraft cooking conditions in laboratory digesters. In addition to measurements of traditional physical parameters, the pulps were characterized using standard 13C CP/MAS NMR spectroscopy. The relationship between the kappa number and both the NMR time domain and frequency domain data was modeled using multivariate data analysis techniques. The variation in the NMR spectra that was not correlated with the kappa number was removed using a new preprocessing tool, orthogonal signal correction (OSC). The resulting OSC-treated NMR spectra were used as descriptors to generate partial least-squares projections to latent structures (PLS) models for the variation of the kappa number. PLS weights were used to generate NMR ‘sub-spectra’ which correspond to changes in the pulps that occur as the pulping process proceeds from high to low values of the kappa number. The sub-spectra were used to gain insight into the changes in the pulps occurring at the molecular level. Concomitant changes in cellulose crystallinity and the amounts of hemicellulose and lignin were observed in these sub-spectra. Copyright © 2001 John Wiley \& Sons, Ltd.},
	language = {en},
	number = {5},
	urldate = {2021-11-02},
	journal = {Magnetic Resonance in Chemistry},
	author = {Hauksson, Jón B. and Edlund, Ulf and Trygg, Johan},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1002/mrc.838},
	keywords = {13C CP/MAS NMR, NMR, kraft pulps, multivariate data analysis, orthogonal signal correction, partial least squares projections to latent structures},
	pages = {267--275},
}

This paper presents a novel way of extracting information from a series of severely overlapped NMR spectra using multivariate data analysis techniques. A number of softwood pulps were prepared from wood chips that were subjected to kraft cooking conditions in laboratory digesters. In addition to measurements of traditional physical parameters, the pulps were characterized using standard 13C CP/MAS NMR spectroscopy. The relationship between the kappa number and both the NMR time domain and frequency domain data was modeled using multivariate data analysis techniques. The variation in the NMR spectra that was not correlated with the kappa number was removed using a new preprocessing tool, orthogonal signal correction (OSC). The resulting OSC-treated NMR spectra were used as descriptors to generate partial least-squares projections to latent structures (PLS) models for the variation of the kappa number. PLS weights were used to generate NMR ‘sub-spectra’ which correspond to changes in the pulps that occur as the pulping process proceeds from high to low values of the kappa number. The sub-spectra were used to gain insight into the changes in the pulps occurring at the molecular level. Concomitant changes in cellulose crystallinity and the amounts of hemicellulose and lignin were observed in these sub-spectra. Copyright © 2001 John Wiley & Sons, Ltd.

@article{nasholm_uptake_2001,
	title = {Uptake of glycine by field grown wheat},
	volume = {150},
	issn = {1469-8137},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1469-8137.2001.00072.x},
	doi = {10/bvc8j6},
	abstract = {• Uptake of glycine, a simple organic nitrogen (N) source, directly from the soil is shown here in a conventionally cropped wheat ( Triticum aestivum ) field. • Wheat plants were harvested after tracer injections into the soil of two forms of dual-labelled amino acid; [ 13C2], [15N]-glycine and 2-[13C], [15N]-glycine. Uptake of intact amino acid was analysed by stable isotope–, and gas chromatography–, mass spectrometry. • Significant increases in 13 C were found in root extracts for all glycine-treated plants. Regression analysis of excess 13 C vs excess 15 N for the two glycine forms showed that at least 20\% of absorbed glycine-N was derived from uptake of intact glycine. Gas chromatography–mass spectrometry was used to verify the presence of intact dual-labelled glycine in wheat roots. Results also indicated that glycine decarboxylase had a minor role in metabolism of absorbed glycine in wheat roots. Microbial metabolism in the soil did, however, result in rapid decarboxylation of added glycine. • Field-grown wheat takes up glycine directly from the soil; the dependence of agricultural plants on nitrate and ammonium as the only forms of available N is therefore questionable.},
	language = {en},
	number = {1},
	urldate = {2021-11-02},
	journal = {New Phytologist},
	author = {Näsholm, Torgny and Huss-Danell, Kerstin and Högberg, Peter},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1469-8137.2001.00072.x},
	keywords = {13C, 15N-glycine, GC-MS, amino acid uptake, ammonium, nitrate, wheat (Triticum aestivum)},
	pages = {59--63},
}

• Uptake of glycine, a simple organic nitrogen (N) source, directly from the soil is shown here in a conventionally cropped wheat ( Triticum aestivum ) field. • Wheat plants were harvested after tracer injections into the soil of two forms of dual-labelled amino acid; [ 13C2], [15N]-glycine and 2-[13C], [15N]-glycine. Uptake of intact amino acid was analysed by stable isotope–, and gas chromatography–, mass spectrometry. • Significant increases in 13 C were found in root extracts for all glycine-treated plants. Regression analysis of excess 13 C vs excess 15 N for the two glycine forms showed that at least 20% of absorbed glycine-N was derived from uptake of intact glycine. Gas chromatography–mass spectrometry was used to verify the presence of intact dual-labelled glycine in wheat roots. Results also indicated that glycine decarboxylase had a minor role in metabolism of absorbed glycine in wheat roots. Microbial metabolism in the soil did, however, result in rapid decarboxylation of added glycine. • Field-grown wheat takes up glycine directly from the soil; the dependence of agricultural plants on nitrate and ammonium as the only forms of available N is therefore questionable.

@article{kang_variation_2001,
	title = {Variation in effective number of clones in seed orchards},
	volume = {21},
	issn = {1573-5095},
	url = {https://doi.org/10.1023/A:1010785222169},
	doi = {10/fv3jmr},
	abstract = {The effective number of clones (Nc) wasestimated for 255 conifer clonal seed orchards in Finland, Korea, andSweden, based on the variation in the number of ramets among clones. Themean census number of clones (N) varied from 70, in 13 KoreanPinus koraiensis seed orchards, to 139 in 176 Finnish Pinussylvestris seed orchards. The mean effective number of clones(Nc) was 66, with a range from 10 to 421. One fifthof the orchards had Nc between 10 and 40, and twothirds between 41 and 160. On average, the relative effective number ofclones (Nr =Nc/N) was 0.74, with a range from 0.2to almost 1.0. Thus, the census number of clones in a seed orchard isgenerally rather informative, but the effective number of clones is moreinformative. Many of these first-generation seed orchards wereestablished with an intention to have near-equal numbers of ramets foreach clone. The use of effective number of clones may be more importantin future seed orchards and genetically thinned seed orchards.},
	language = {en},
	number = {1},
	urldate = {2021-11-02},
	journal = {New Forests},
	author = {Kang, K.S. and Harju, A.M. and Lindgren, D. and Nikkanen, T. and Almqvist, C. and Suh, G.U.},
	month = jan,
	year = {2001},
	pages = {17--33},
}

The effective number of clones (Nc) wasestimated for 255 conifer clonal seed orchards in Finland, Korea, andSweden, based on the variation in the number of ramets among clones. Themean census number of clones (N) varied from 70, in 13 KoreanPinus koraiensis seed orchards, to 139 in 176 Finnish Pinussylvestris seed orchards. The mean effective number of clones(Nc) was 66, with a range from 10 to 421. One fifthof the orchards had Nc between 10 and 40, and twothirds between 41 and 160. On average, the relative effective number ofclones (Nr =Nc/N) was 0.74, with a range from 0.2to almost 1.0. Thus, the census number of clones in a seed orchard isgenerally rather informative, but the effective number of clones is moreinformative. Many of these first-generation seed orchards wereestablished with an intention to have near-equal numbers of ramets foreach clone. The use of effective number of clones may be more importantin future seed orchards and genetically thinned seed orchards.

@article{lipson_unexpected_2001,
	title = {The unexpected versatility of plants: organic nitrogen use and availability in terrestrial ecosystems},
	volume = {128},
	issn = {1432-1939},
	shorttitle = {The unexpected versatility of plants},
	url = {https://doi.org/10.1007/s004420100693},
	doi = {10/bvv52v},
	abstract = {The recently recognized importance of organic nitrogen (ON), particularly amino acids, to plant nutrition in many types of agricultural and natural ecosystems has raised questions about plant-microbe interactions, N availability in soils, and the ecological implications of ON use by plants in the light of climate change and N pollution. In this review we synthesize the recent work on availability and plant uptake of amino acids with classic work on ON in soils. We also discuss recent work on the use of natural abundance levels of 15N to infer N sources for plants. Reliance on ON is widespread among plants from many ecosystems. Authors have reached this conclusion based on laboratory studies of amino acid uptake by plants in pure culture, amino acid concentrations in soils, plant uptake of isotopically labeled amino acids in the field and in plant-soil microcosms, and from plant natural abundance values of 15N. The supply of amino acids to plants is determined mainly by the action of soil proteolytic enzymes, interactions between amino acids and the soil matrix, and competition between plants and microbes. Plants generally compete for a minor fraction of the total amino acid flux, but in some cases this forms a significant N resource, especially in ecosystems where microbial biomass undergoes large seasonal fluctuations and contributes labile ON to the soil. A quantitative understanding of ON use by plants is confounded by incomplete data on partitioning of ON between plants, mycorrhizal fungi, and competing soil microbes. Further research is needed to predict the ecological implications of ON use by plants given the influence of climatic change and N pollution.},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Oecologia},
	author = {Lipson, David and Näsholm, Torgny},
	month = aug,
	year = {2001},
	pages = {305--316},
}

The recently recognized importance of organic nitrogen (ON), particularly amino acids, to plant nutrition in many types of agricultural and natural ecosystems has raised questions about plant-microbe interactions, N availability in soils, and the ecological implications of ON use by plants in the light of climate change and N pollution. In this review we synthesize the recent work on availability and plant uptake of amino acids with classic work on ON in soils. We also discuss recent work on the use of natural abundance levels of 15N to infer N sources for plants. Reliance on ON is widespread among plants from many ecosystems. Authors have reached this conclusion based on laboratory studies of amino acid uptake by plants in pure culture, amino acid concentrations in soils, plant uptake of isotopically labeled amino acids in the field and in plant-soil microcosms, and from plant natural abundance values of 15N. The supply of amino acids to plants is determined mainly by the action of soil proteolytic enzymes, interactions between amino acids and the soil matrix, and competition between plants and microbes. Plants generally compete for a minor fraction of the total amino acid flux, but in some cases this forms a significant N resource, especially in ecosystems where microbial biomass undergoes large seasonal fluctuations and contributes labile ON to the soil. A quantitative understanding of ON use by plants is confounded by incomplete data on partitioning of ON between plants, mycorrhizal fungi, and competing soil microbes. Further research is needed to predict the ecological implications of ON use by plants given the influence of climatic change and N pollution.

@article{trygg_2d_2001,
	title = {{2D} wavelet analysis and compression of on-line industrial process data},
	volume = {15},
	issn = {1099-128X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/cem.681},
	doi = {10.1002/cem.681},
	abstract = {In recent years the wavelet transform (WT) has interested a large number of scientists from many different fields. Pattern recognition, signal processing, signal compression, process monitoring and control, and image analysis are some areas where wavelets have shown promising results. In this paper, 2D wavelet analysis and compression of near-infrared spectra for on-line monitoring of wood chips is reviewed. We introduce a new parameter for outlier detection, distance to model in wavelet space (DModW), which is analogous to the residual parameter (DModX) used in principal component analysis (PCA) and partial least squares analysis (PLS). Additionally, we describe the wavelet power spectrum (WPS), the wavelet analogue of the power spectrum. The WPS gives an overview of the time–frequency content in a signal. In the example given, wavelets improved the detection of spectral shift and compressed data 1000-fold without degrading the quality of the 2D wavelet-compressed PCA model. The example concerned an industrial process-monitoring situation where near-infrared spectra are measured on-line on top of a conveyer belt filled with wood chips at a Swedish pulp plant. Copyright © 2001 John Wiley \& Sons, Ltd.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Journal of Chemometrics},
	author = {Trygg, Johan and Kettaneh-Wold, Nouna and Wallbäcks, Lars},
	year = {2001},
	keywords = {2D wavelet transform, NIR, near-infrared spectroscopy, on-line process monitoring, outlier detection, time series compression, wavelet power spectrum},
	pages = {299--319},
}

In recent years the wavelet transform (WT) has interested a large number of scientists from many different fields. Pattern recognition, signal processing, signal compression, process monitoring and control, and image analysis are some areas where wavelets have shown promising results. In this paper, 2D wavelet analysis and compression of near-infrared spectra for on-line monitoring of wood chips is reviewed. We introduce a new parameter for outlier detection, distance to model in wavelet space (DModW), which is analogous to the residual parameter (DModX) used in principal component analysis (PCA) and partial least squares analysis (PLS). Additionally, we describe the wavelet power spectrum (WPS), the wavelet analogue of the power spectrum. The WPS gives an overview of the time–frequency content in a signal. In the example given, wavelets improved the detection of spectral shift and compressed data 1000-fold without degrading the quality of the 2D wavelet-compressed PCA model. The example concerned an industrial process-monitoring situation where near-infrared spectra are measured on-line on top of a conveyer belt filled with wood chips at a Swedish pulp plant. Copyright © 2001 John Wiley & Sons, Ltd.

@article{albrectsen_female-biased_2001,
	title = {Female-biased density-dependent dispersal of a tephritid fly in a fragmented habitat and its implications for population regulation},
	volume = {94},
	issn = {1600-0706},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1600-0706.2001.940206.x},
	doi = {10.1034/j.1600-0706.2001.940206.x},
	abstract = {The aim of this study was to quantify the rate of dispersal as a response to density in the specialist tephritid fly Paroxyna plantaginis (the main seed predator on its patchily distributed host plant, Tripolium vulgare, Asteraceae). Marked flies were released at three different fly densities in artificial host patches. The individual histories of recaptures were recorded as well as migration between patches and invasion by unmarked flies. The loss of marked flies relative to initial density was analysed using maximum likelihood estimation. Females generally had the highest loss rate. When comparing a density-independent model with a density-dependent model of the loss rate, the density-dependent model won four times out of six for the females but not a single time for the males. A stronger immigration rate of females relative to males supported the suggested female-biased dispersal. This indicates a sit-and-wait strategy for the territorial males and a pre-emptive competition strategy for egg-laying substrates for the females. These results may be of general importance for non-frugivorous tephritid systems with unpredictable and almost ephemeral accessibility to host plants and with a dynamics characterised by a high turnover rate and high attack levels. The study presents a method for measuring the propensity of individuals to leave an area as a response to local density. It is further an example of the consequences individual behavioural responses may have on the population dynamics of a patchy population.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Oikos},
	author = {Albrectsen, Benedicte and Nachman, Gösta},
	year = {2001},
	pages = {263--272},
}

The aim of this study was to quantify the rate of dispersal as a response to density in the specialist tephritid fly Paroxyna plantaginis (the main seed predator on its patchily distributed host plant, Tripolium vulgare, Asteraceae). Marked flies were released at three different fly densities in artificial host patches. The individual histories of recaptures were recorded as well as migration between patches and invasion by unmarked flies. The loss of marked flies relative to initial density was analysed using maximum likelihood estimation. Females generally had the highest loss rate. When comparing a density-independent model with a density-dependent model of the loss rate, the density-dependent model won four times out of six for the females but not a single time for the males. A stronger immigration rate of females relative to males supported the suggested female-biased dispersal. This indicates a sit-and-wait strategy for the territorial males and a pre-emptive competition strategy for egg-laying substrates for the females. These results may be of general importance for non-frugivorous tephritid systems with unpredictable and almost ephemeral accessibility to host plants and with a dynamics characterised by a high turnover rate and high attack levels. The study presents a method for measuring the propensity of individuals to leave an area as a response to local density. It is further an example of the consequences individual behavioural responses may have on the population dynamics of a patchy population.

@article{gietl_ricinosomes_2001,
	title = {Ricinosomes: an organelle for developmentally regulated programmed cell death in senescing plant tissues},
	volume = {88},
	issn = {1432-1904},
	shorttitle = {Ricinosomes},
	url = {https://doi.org/10.1007/s001140000203},
	doi = {10.1007/s001140000203},
	abstract = {This review describes aspects of programmed cell death (PCD). Present research maps the enzymes involved and explores the signal transduction pathways involved in their synthesis. A special organelle (the ricinosome) has been discovered in the senescing endosperm of germinating castor beans (Ricinus communis) that develops at the beginning of PCD and delivers large amounts of a papain-type cysteine endopeptidase (CysEP) in the final stages of cellular disintegration. Castor beans store oil and proteins in a living endosperm surrounding the cotyledons. These stores are mobilized during germination and transferred into the cotyledons. PCD is initiated after this transfer is complete. The CysEP is synthesized in the lumen of the endoplasmic reticulum (ER) where it is retained by its C-terminal KDEL peptide as a rather inactive pro-enzyme. Large number of ricinosomes bud from the ER at the same time as the nuclear DNA is characteristically fragmented during PCD. The mitochondria, glyoxysomes and ribosomes are degraded in autophagic vacuoles, while the endopeptidase is activated by removal of the propeptide and the KDEL tail and enters the cytosol. The endosperm dries and detaches from the cotyledons. A homologous KDEL-tailed cysteine endopeptidase has been found in several senescing tissues; it has been localized in ricinosomes of withering day-lily petals and dying seed coats. Three genes for a KDEL-tailed cysteine endopeptidase have been identified in Arabidopsis. One is expressed in senescing ovules, the second in the vascular vessels and the third in maturing siliques. These genes open the way to exploring PCD in plants.},
	language = {en},
	number = {2},
	urldate = {2021-10-22},
	journal = {Naturwissenschaften},
	author = {Gietl, C. and Schmid, M.},
	month = feb,
	year = {2001},
	pages = {49--58},
}

This review describes aspects of programmed cell death (PCD). Present research maps the enzymes involved and explores the signal transduction pathways involved in their synthesis. A special organelle (the ricinosome) has been discovered in the senescing endosperm of germinating castor beans (Ricinus communis) that develops at the beginning of PCD and delivers large amounts of a papain-type cysteine endopeptidase (CysEP) in the final stages of cellular disintegration. Castor beans store oil and proteins in a living endosperm surrounding the cotyledons. These stores are mobilized during germination and transferred into the cotyledons. PCD is initiated after this transfer is complete. The CysEP is synthesized in the lumen of the endoplasmic reticulum (ER) where it is retained by its C-terminal KDEL peptide as a rather inactive pro-enzyme. Large number of ricinosomes bud from the ER at the same time as the nuclear DNA is characteristically fragmented during PCD. The mitochondria, glyoxysomes and ribosomes are degraded in autophagic vacuoles, while the endopeptidase is activated by removal of the propeptide and the KDEL tail and enters the cytosol. The endosperm dries and detaches from the cotyledons. A homologous KDEL-tailed cysteine endopeptidase has been found in several senescing tissues; it has been localized in ricinosomes of withering day-lily petals and dying seed coats. Three genes for a KDEL-tailed cysteine endopeptidase have been identified in Arabidopsis. One is expressed in senescing ovules, the second in the vascular vessels and the third in maturing siliques. These genes open the way to exploring PCD in plants.

@article{mattsson_frankia_2001,
	title = {Frankia {KB5} {Possesses} a {Hydrogenase} {Immunologically} {Related} to {Membrane}-{Bound} [{NiFe}]-{Hydrogenases}},
	volume = {42},
	issn = {1432-0991},
	url = {https://doi.org/10.1007/s002840010244},
	doi = {10.1007/s002840010244},
	abstract = {The immunological relationship of the hydrogenase in Frankia KB5 to hydrogenases in other microorganisms was investigated using antisera raised against holo-[NiFe]-hydrogenases isolated from Alcaligenes latus, Azotobacter vinelandii, Ralstonia eutropha, and the small and large hydrogenase subunits from Bradyrhizobium japonicum. The antisera raised against the A. latus, R. eutropha, and B. japonicum (large subunit) polypeptides were found to recognize two polypeptides, corresponding to the unprocessed and processed forms of the hydrogenase subunit in Frankia KB5. None of the antisera, including the antibodies produced against the small hydrogenase subunit isolated from B. japonicum, recognized any polypeptide related to the small hydrogenase subunit in Frankia KB5. An immunogold localization study of the intracellular distribution of hydrogenase in Frankia KB5, with the cryo-section technique, showed that labeling in the membrane of both hyphae and vesicles was positively correlated with hydrogenase activity.},
	language = {en},
	number = {6},
	urldate = {2021-11-02},
	journal = {Current Microbiology},
	author = {Mattsson, Ulrika and Johansson, Lenore and Sandström, Gunnar and Sellstedt, Anita},
	month = jun,
	year = {2001},
	pages = {438--441},
}

The immunological relationship of the hydrogenase in Frankia KB5 to hydrogenases in other microorganisms was investigated using antisera raised against holo-[NiFe]-hydrogenases isolated from Alcaligenes latus, Azotobacter vinelandii, Ralstonia eutropha, and the small and large hydrogenase subunits from Bradyrhizobium japonicum. The antisera raised against the A. latus, R. eutropha, and B. japonicum (large subunit) polypeptides were found to recognize two polypeptides, corresponding to the unprocessed and processed forms of the hydrogenase subunit in Frankia KB5. None of the antisera, including the antibodies produced against the small hydrogenase subunit isolated from B. japonicum, recognized any polypeptide related to the small hydrogenase subunit in Frankia KB5. An immunogold localization study of the intracellular distribution of hydrogenase in Frankia KB5, with the cryo-section technique, showed that labeling in the membrane of both hyphae and vesicles was positively correlated with hydrogenase activity.

@article{swarup_localization_2001,
	title = {Localization of the auxin permease {AUX1} suggests two functionally distinct hormone transport pathways operate in the {Arabidopsis} root apex},
	volume = {15},
	url = {https://www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC312818/},
	doi = {10.1101/gad.210501},
	abstract = {Auxins represent an important class of plant hormone that regulate plant development. Plants use specialized carrier proteins to transport the auxin indole-3-acetic acid (IAA) to target tissues. To date, efflux carrier-mediated polar auxin transport has ...},
	language = {en},
	number = {20},
	urldate = {2021-11-02},
	journal = {Genes \& Development},
	author = {Swarup, Ranjan and Friml, Jirí and Marchant, Alan and Ljung, Karin and Sandberg, Goran and Palme, Klaus and Bennett, Malcolm},
	month = oct,
	year = {2001},
	pmid = {11641271},
	note = {Publisher: Cold Spring Harbor Laboratory Press},
	keywords = {AUX1, Auxin transport, auxin influx carrier, membrane localization, phloem unloading, root gravitropism},
	pages = {2648},
}

Auxins represent an important class of plant hormone that regulate plant development. Plants use specialized carrier proteins to transport the auxin indole-3-acetic acid (IAA) to target tissues. To date, efflux carrier-mediated polar auxin transport has ...

@article{chen_role_2001,
	title = {The role of auxin-binding protein 1 in the expansion of tobacco leaf cells},
	volume = {28},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2001.01152.x},
	doi = {10.1046/j.1365-313x.2001.01152.x},
	abstract = {Tobacco leaf was used to investigate the mechanism of action of auxin-binding protein 1 (ABP1). The distributions of free auxin, ABP1, percentage of leaf nuclei in G2 and the amount of auxin-inducible growth were each determined in control tobacco leaves and leaves over-expressing Arabidopsis ABP1. These parameters were compared with growth of tobacco leaves, measured both spatially and temporally throughout the entire expansion phase. Within a defined window of leaf development, juvenile leaf cells that inducibly expressed Arabidopsis ABP1 prematurely advanced nuclei to the G2 phase. The ABP1-induced increase in cell expansion occured before the advance to the G2 phase, indicating that the ABP1-induced G2 phase advance is an indirect effect of cell expansion. The level of ABP1 was highest at the position of maximum cell expansion, maximum auxin-inducible growth and where the free auxin level was the lowest. In contrast, the position of maximum cell division correlated with higher auxin levels and lower ABP1 levels. Consistent with the correlations observed in leaves, tobacco cells (BY-2) in culture displayed two dose-dependent responses to auxin. At a low auxin concentration, cells expanded, while at a relatively higher concentration, cells divided and incorporated [3H]-thymidine. Antisense suppression of ABP1 in these cells dramatically reduced cell expansion with negligible effect on cell division. Taken together, the data suggest that ABP1 acts at a relatively low level of auxin to mediate cell expansion, whereas high auxin levels stimulate cell division via an unidentified receptor.},
	language = {en},
	number = {6},
	urldate = {2021-11-02},
	journal = {The Plant Journal},
	author = {Chen, Jin-Gui and Shimomura, Shoji and Sitbon, Folke and Sandberg, Göran and Jones, Alan M},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2001.01152.x},
	keywords = {ABP1, auxin, cell division, cell expansion, leaf growth, nuclear cycle},
	pages = {607--617},
}

Tobacco leaf was used to investigate the mechanism of action of auxin-binding protein 1 (ABP1). The distributions of free auxin, ABP1, percentage of leaf nuclei in G2 and the amount of auxin-inducible growth were each determined in control tobacco leaves and leaves over-expressing Arabidopsis ABP1. These parameters were compared with growth of tobacco leaves, measured both spatially and temporally throughout the entire expansion phase. Within a defined window of leaf development, juvenile leaf cells that inducibly expressed Arabidopsis ABP1 prematurely advanced nuclei to the G2 phase. The ABP1-induced increase in cell expansion occured before the advance to the G2 phase, indicating that the ABP1-induced G2 phase advance is an indirect effect of cell expansion. The level of ABP1 was highest at the position of maximum cell expansion, maximum auxin-inducible growth and where the free auxin level was the lowest. In contrast, the position of maximum cell division correlated with higher auxin levels and lower ABP1 levels. Consistent with the correlations observed in leaves, tobacco cells (BY-2) in culture displayed two dose-dependent responses to auxin. At a low auxin concentration, cells expanded, while at a relatively higher concentration, cells divided and incorporated [3H]-thymidine. Antisense suppression of ABP1 in these cells dramatically reduced cell expansion with negligible effect on cell division. Taken together, the data suggest that ABP1 acts at a relatively low level of auxin to mediate cell expansion, whereas high auxin levels stimulate cell division via an unidentified receptor.

@article{sundberg_effect_2001,
	title = {The effect of nitrogen on growth and key thallus components in the two tripartite lichens, {Nephroma} arcticum and {Peltigera} aphthosa},
	volume = {24},
	issn = {1365-3040},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-3040.2001.00701.x},
	doi = {10.1046/j.1365-3040.2001.00701.x},
	abstract = {Relationships between growth, nitrogen and concentration of unique biont components were investigated for the tripartite lichens Nephroma arcticum (L.) Torss. and Peltigera aphthosa (L.) Willd. Nitrogen availability was manipulated during 4 summer months by removing cephalodia and their associated N2 fixation activity, or by weekly irrigation with NH4NO3. Chlorophyll and ribulose 1·5-biphosphate carboxylase/oxygenase (Rubisco), and chitin and ergosterol were used as photobiont and mycobiont markers, respectively. Nitrogen concentrations were similar in older and newer parts of the same thallus, varying between 2 and 5 g m−2, with P. aphthosa having higher concentrations than N. arcticum. Both chlorophyll (Chl a) and chitin were linearly correlated with thallus N, but N. arcticum invested more in fungal biomass and had lower Chl a concentrations in comparison with P. aphthosa at equal thallus N. During the 4 months, control and N-fertilized thalli of N. arcticum increased in area by 0·2 m2 m−2 and P. aphthosa by 0·4 m2 m−2. Thallus expansion was significantly inhibited in samples without cephalodia, but there was no effect on lichen weight gain. Mean relative growth rate (RGR; mg g−1 d−1) was 3·8 for N. arcticum and 8·4 for P. aphthosa, when time (d) reflected the lichen wet periods. RGR was 2–3 times lower when based on the whole time, i.e. when including dry periods. The efficiency (e) of converting incident irradiance into lichen biomass was positively and linearly correlated with thallus Chl a concentration to the same extent in both species. The slower growth rates of N. arcticum, in comparison with P. aphthosa, could then be explained by their lower nitrogen and Chl a concentrations and a subsequently lower light energy conversion efficiency. Functional and dynamic aspects of resource allocation patterns of the two lichens are discussed in relation to the above findings.},
	language = {en},
	number = {5},
	urldate = {2021-11-02},
	journal = {Plant, Cell \& Environment},
	author = {Sundberg, B. and Näsholm, T. and Palmqvist, K.},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-3040.2001.00701.x},
	keywords = {chitin, chlorophyll, ergosterol, lichen growth, light use efficiency, resource allocation},
	pages = {517--527},
}

Relationships between growth, nitrogen and concentration of unique biont components were investigated for the tripartite lichens Nephroma arcticum (L.) Torss. and Peltigera aphthosa (L.) Willd. Nitrogen availability was manipulated during 4 summer months by removing cephalodia and their associated N2 fixation activity, or by weekly irrigation with NH4NO3. Chlorophyll and ribulose 1·5-biphosphate carboxylase/oxygenase (Rubisco), and chitin and ergosterol were used as photobiont and mycobiont markers, respectively. Nitrogen concentrations were similar in older and newer parts of the same thallus, varying between 2 and 5 g m−2, with P. aphthosa having higher concentrations than N. arcticum. Both chlorophyll (Chl a) and chitin were linearly correlated with thallus N, but N. arcticum invested more in fungal biomass and had lower Chl a concentrations in comparison with P. aphthosa at equal thallus N. During the 4 months, control and N-fertilized thalli of N. arcticum increased in area by 0·2 m2 m−2 and P. aphthosa by 0·4 m2 m−2. Thallus expansion was significantly inhibited in samples without cephalodia, but there was no effect on lichen weight gain. Mean relative growth rate (RGR; mg g−1 d−1) was 3·8 for N. arcticum and 8·4 for P. aphthosa, when time (d) reflected the lichen wet periods. RGR was 2–3 times lower when based on the whole time, i.e. when including dry periods. The efficiency (e) of converting incident irradiance into lichen biomass was positively and linearly correlated with thallus Chl a concentration to the same extent in both species. The slower growth rates of N. arcticum, in comparison with P. aphthosa, could then be explained by their lower nitrogen and Chl a concentrations and a subsequently lower light energy conversion efficiency. Functional and dynamic aspects of resource allocation patterns of the two lichens are discussed in relation to the above findings.

@article{moroney_carbonic_2001,
	title = {Carbonic anhydrases in plants and algae},
	volume = {24},
	issn = {1365-3040},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-3040.2001.00669.x},
	doi = {10.1111/j.1365-3040.2001.00669.x},
	abstract = {Carbonic anhydrases catalyse the reversible hydration of CO2, increasing the interconversion between CO2 and HCO3− + H+ in living organisms. The three evolutionarily unrelated families of carbonic anhydrases are designated α-, β-and γ-CA. Animals have only the α-carbonic anhydrase type of carbonic anhydrase, but they contain multiple isoforms of this carbonic anhydrase. In contrast, higher plants, algae and cyanobacteria may contain members of all three CA families. Analysis of the Arabidopsis database reveals at least 14 genes potentially encoding carbonic anhydrases. The database also contains expressed sequence tags (ESTs) with homology to most of these genes. Clearly the number of carbonic anhydrases in plants is much greater than previously thought. Chlamydomonas, a unicellular green alga, is not far behind with five carbonic anhydrases already identified and another in the EST database. In algae, carbonic anhydrases have been found in the mitochondria, the chloroplast thylakoid, the cytoplasm and the periplasmic space. In C3 dicots, only two carbonic anhydrases have been localized, one to the chloroplast stroma and one to the cytoplasm. A challenge for plant scientists is to identify the number, location and physiological roles of the carbonic anhydrases.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Plant, Cell \& Environment},
	author = {Moroney, J. V. and Bartlett, S. G. and Samuelsson, G.},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-3040.2001.00669.x},
	keywords = {Arabidopsis, Chlamydomonas, cyanobacteria, macro-algae, photosynthesis},
	pages = {141--153},
}

Carbonic anhydrases catalyse the reversible hydration of CO2, increasing the interconversion between CO2 and HCO3− + H+ in living organisms. The three evolutionarily unrelated families of carbonic anhydrases are designated α-, β-and γ-CA. Animals have only the α-carbonic anhydrase type of carbonic anhydrase, but they contain multiple isoforms of this carbonic anhydrase. In contrast, higher plants, algae and cyanobacteria may contain members of all three CA families. Analysis of the Arabidopsis database reveals at least 14 genes potentially encoding carbonic anhydrases. The database also contains expressed sequence tags (ESTs) with homology to most of these genes. Clearly the number of carbonic anhydrases in plants is much greater than previously thought. Chlamydomonas, a unicellular green alga, is not far behind with five carbonic anhydrases already identified and another in the EST database. In algae, carbonic anhydrases have been found in the mitochondria, the chloroplast thylakoid, the cytoplasm and the periplasmic space. In C3 dicots, only two carbonic anhydrases have been localized, one to the chloroplast stroma and one to the cytoplasm. A challenge for plant scientists is to identify the number, location and physiological roles of the carbonic anhydrases.

@article{reintanz_bus_2001,
	title = {bus, a {Bushy} {Arabidopsis} {CYP79F1} {Knockout} {Mutant} with {Abolished} {Synthesis} of {Short}-{Chain} {Aliphatic} {Glucosinolates}},
	volume = {13},
	issn = {1040-4651},
	url = {https://doi.org/10.1105/tpc.13.2.351},
	doi = {10.1105/tpc.13.2.351},
	abstract = {A new mutant of Arabidopsis designated bus1-1 (for bushy), which exhibited a bushy phenotype with crinkled leaves and retarded vascularization, was characterized. The phenotype was caused by an En-1 insertion in the gene CYP79F1. The deduced protein belongs to the cytochrome P450 superfamily. Because members of the CYP79 subfamily are believed to catalyze the oxidation of amino acids to aldoximes, the initial step in glucosinolate biosynthesis, we analyzed the level of glucosinolates in a CYP79F1 null mutant (bus1-1f) and in an overexpressing plant. Short-chain glucosinolates derived from methionine were completely lacking in the null mutant and showed increased levels in the overexpressing plant, indicating that CYP79F1 uses short-chain methionine derivatives as substrates. In addition, the concentrations of indole-3-ylmethyl-glucosinolate and the content of the auxin indole-3-acetic acid and its precursor indole-3-acetonitrile were increased in the bus1-1f mutant. Our results demonstrate for the first time that the formation of glucosinolates derived from methionine is mediated by CYP79F1 and that knocking out this cytochrome P450 has profound effects on plant growth and development.},
	number = {2},
	urldate = {2021-11-02},
	journal = {The Plant Cell},
	author = {Reintanz, Birgit and Lehnen, Michaela and Reichelt, Michael and Gershenzon, Jonathan and Kowalczyk, Marius and Sandberg, Goran and Godde, Matthias and Uhl, Rainer and Palme, Klaus},
	month = feb,
	year = {2001},
	pages = {351--367},
}

A new mutant of Arabidopsis designated bus1-1 (for bushy), which exhibited a bushy phenotype with crinkled leaves and retarded vascularization, was characterized. The phenotype was caused by an En-1 insertion in the gene CYP79F1. The deduced protein belongs to the cytochrome P450 superfamily. Because members of the CYP79 subfamily are believed to catalyze the oxidation of amino acids to aldoximes, the initial step in glucosinolate biosynthesis, we analyzed the level of glucosinolates in a CYP79F1 null mutant (bus1-1f) and in an overexpressing plant. Short-chain glucosinolates derived from methionine were completely lacking in the null mutant and showed increased levels in the overexpressing plant, indicating that CYP79F1 uses short-chain methionine derivatives as substrates. In addition, the concentrations of indole-3-ylmethyl-glucosinolate and the content of the auxin indole-3-acetic acid and its precursor indole-3-acetonitrile were increased in the bus1-1f mutant. Our results demonstrate for the first time that the formation of glucosinolates derived from methionine is mediated by CYP79F1 and that knocking out this cytochrome P450 has profound effects on plant growth and development.

@article{casimiro_auxin_2001,
	title = {Auxin {Transport} {Promotes} {Arabidopsis} {Lateral} {Root} {Initiation}},
	volume = {13},
	issn = {1040-4651},
	url = {https://doi.org/10.1105/tpc.13.4.843},
	doi = {10.1105/tpc.13.4.843},
	abstract = {Lateral root development in Arabidopsis provides a model for the study of hormonal signals that regulate postembryonic organogenesis in higher plants. Lateral roots originate from pairs of pericycle cells, in several cell files positioned opposite the xylem pole, that initiate a series of asymmetric, transverse divisions. The auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) arrests lateral root development by blocking the first transverse division(s). We investigated the basis of NPA action by using a cell-specific reporter to demonstrate that xylem pole pericycle cells retain their identity in the presence of the auxin transport inhibitor. However, NPA causes indoleacetic acid (IAA) to accumulate in the root apex while reducing levels in basal tissues critical for lateral root initiation. This pattern of IAA redistribution is consistent with NPA blocking basipetal IAA movement from the root tip. Characterization of lateral root development in the shoot meristemless1 mutant demonstrates that root basipetal and leaf acropetal auxin transport activities are required during the initiation and emergence phases, respectively, of lateral root development.},
	number = {4},
	urldate = {2021-11-02},
	journal = {The Plant Cell},
	author = {Casimiro, Ilda and Marchant, Alan and Bhalerao, Rishikesh P. and Beeckman, Tom and Dhooge, Sandra and Swarup, Ranjan and Graham, Neil and Inzé, Dirk and Sandberg, Goran and Casero, Pedro J. and Bennett, Malcolm},
	month = apr,
	year = {2001},
	pages = {843--852},
}

Lateral root development in Arabidopsis provides a model for the study of hormonal signals that regulate postembryonic organogenesis in higher plants. Lateral roots originate from pairs of pericycle cells, in several cell files positioned opposite the xylem pole, that initiate a series of asymmetric, transverse divisions. The auxin transport inhibitor N-1-naphthylphthalamic acid (NPA) arrests lateral root development by blocking the first transverse division(s). We investigated the basis of NPA action by using a cell-specific reporter to demonstrate that xylem pole pericycle cells retain their identity in the presence of the auxin transport inhibitor. However, NPA causes indoleacetic acid (IAA) to accumulate in the root apex while reducing levels in basal tissues critical for lateral root initiation. This pattern of IAA redistribution is consistent with NPA blocking basipetal IAA movement from the root tip. Characterization of lateral root development in the shoot meristemless1 mutant demonstrates that root basipetal and leaf acropetal auxin transport activities are required during the initiation and emergence phases, respectively, of lateral root development.

@article{andersson_antisense_2001,
	title = {Antisense {Inhibition} of the {Photosynthetic} {Antenna} {Proteins} {CP29} and {CP26}: {Implications} for the {Mechanism} of {Protective} {Energy} {Dissipation}},
	volume = {13},
	issn = {1040-4651},
	shorttitle = {Antisense {Inhibition} of the {Photosynthetic} {Antenna} {Proteins} {CP29} and {CP26}},
	url = {https://doi.org/10.1105/tpc.13.5.1193},
	doi = {10.1105/tpc.13.5.1193},
	abstract = {The specific roles of the chlorophyll a/b binding proteins CP29 and CP26 in light harvesting and energy dissipation within the photosynthetic apparatus have been investigated. Arabidopsis was transformed with antisense constructs against the genes encoding the CP29 or CP26 apoprotein, which gave rise to several transgenic lines with remarkably low amounts of the antisense target proteins. The decrease in the level of CP24 protein in the CP29 antisense lines indicates a physical interaction between these complexes. Analysis of chlorophyll fluorescence showed that removal of the proteins affected photosystem II function, probably as a result of changes in the organization of the light-harvesting antenna. However, whole plant measurements showed that overall photosynthetic rates were similar to those in the wild type. Both antisense lines were capable of the qE type of nonphotochemical fluorescence quenching, although there were minor changes in the capacity for quenching and in its induction kinetics. High-light-induced violaxanthin deepoxidation to zeaxanthin was not affected, although the pool size of these pigments was decreased slightly. We conclude that CP29 and CP26 are unlikely to be sites for nonphotochemical quenching.},
	number = {5},
	urldate = {2021-11-02},
	journal = {The Plant Cell},
	author = {Andersson, Jenny and Walters, Robin G. and Horton, Peter and Jansson, Stefan},
	month = may,
	year = {2001},
	pages = {1193--1204},
}

The specific roles of the chlorophyll a/b binding proteins CP29 and CP26 in light harvesting and energy dissipation within the photosynthetic apparatus have been investigated. Arabidopsis was transformed with antisense constructs against the genes encoding the CP29 or CP26 apoprotein, which gave rise to several transgenic lines with remarkably low amounts of the antisense target proteins. The decrease in the level of CP24 protein in the CP29 antisense lines indicates a physical interaction between these complexes. Analysis of chlorophyll fluorescence showed that removal of the proteins affected photosystem II function, probably as a result of changes in the organization of the light-harvesting antenna. However, whole plant measurements showed that overall photosynthetic rates were similar to those in the wild type. Both antisense lines were capable of the qE type of nonphotochemical fluorescence quenching, although there were minor changes in the capacity for quenching and in its induction kinetics. High-light-induced violaxanthin deepoxidation to zeaxanthin was not affected, although the pool size of these pigments was decreased slightly. We conclude that CP29 and CP26 are unlikely to be sites for nonphotochemical quenching.

@article{chamarro_metabolism_2001,
	title = {Metabolism of indole-3-acetic acid by orange ({Citrus} sinensis) flavedo tissue during fruit development},
	volume = {57},
	issn = {0031-9422},
	url = {https://www.sciencedirect.com/science/article/pii/S0031942201000231},
	doi = {10.1016/S0031-9422(01)00023-1},
	abstract = {[5-3H, 1′-14C, 13C6, 12C] Indole-3-acetic acid (IAA), was applied to the flavedo (epicarp) of intact orange fruits at different stages of development. After incubation in the dark, at 25°C, the tissue was extracted with MeOH and the partially purified extracts were analyzed by reversed phase HPLC-RC. Six major metabolite peaks were detected and subsequently analyzed by combined HPLC-frit-FAB–MS. The metabolite peak 6 contained oxindole-3-acetic acid (OxIAA), indole-3-acetyl-N-aspartic acid (IAAsp) and also indole-3-acetyl-N-glutamic acid (IAGlu). The nature of metabolite 5 remains unknown. Metabolites 3 and 4 were diastereomers of oxindole-3-acetyl-N-aspartic acid (OxIAAsp). Metabolite 2 was identified as dioxindole-3-acetic acid and metabolite 1 as a DiOxIAA linked in position three to a hexose, which is suggested to be 3-(-O-β-glucosyl) dioxindole-3-acetic acid (DiOxIAGlc). Identification work as well as feeding experiments with the [5-3H]IAA labeled metabolites suggest that IAA is metabolized in flavedo tissue mainly through two pathways, namely IAA–OxIAA–DiOxIAA–DiOxIAGlc and IAA–IAAsp–OxIAAsp. The flavedo of citrus fruit has a high capacity for IAA catabolism until the beginning of fruit senescence, with the major route having DiOxIAGlc as end product. This capacity is operative even at high IAA concentrations and is accelerated by pretreatment with the synthetic auxins 2,4-D, NAA and the gibberellin GA3.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Phytochemistry},
	author = {Chamarro, Jesús and Östin, Anders and Sandberg, Göran},
	month = may,
	year = {2001},
	keywords = {Aurantoideae, Flavedo, Gas chromatography–mass spectrometry, High performance liquid chromatography, Indole-3-acetic acid metabolism, Orange fruit, cv. Washington Navel},
	pages = {179--187},
}

[5-3H, 1′-14C, 13C6, 12C] Indole-3-acetic acid (IAA), was applied to the flavedo (epicarp) of intact orange fruits at different stages of development. After incubation in the dark, at 25°C, the tissue was extracted with MeOH and the partially purified extracts were analyzed by reversed phase HPLC-RC. Six major metabolite peaks were detected and subsequently analyzed by combined HPLC-frit-FAB–MS. The metabolite peak 6 contained oxindole-3-acetic acid (OxIAA), indole-3-acetyl-N-aspartic acid (IAAsp) and also indole-3-acetyl-N-glutamic acid (IAGlu). The nature of metabolite 5 remains unknown. Metabolites 3 and 4 were diastereomers of oxindole-3-acetyl-N-aspartic acid (OxIAAsp). Metabolite 2 was identified as dioxindole-3-acetic acid and metabolite 1 as a DiOxIAA linked in position three to a hexose, which is suggested to be 3-(-O-β-glucosyl) dioxindole-3-acetic acid (DiOxIAGlc). Identification work as well as feeding experiments with the [5-3H]IAA labeled metabolites suggest that IAA is metabolized in flavedo tissue mainly through two pathways, namely IAA–OxIAA–DiOxIAA–DiOxIAGlc and IAA–IAAsp–OxIAAsp. The flavedo of citrus fruit has a high capacity for IAA catabolism until the beginning of fruit senescence, with the major route having DiOxIAGlc as end product. This capacity is operative even at high IAA concentrations and is accelerated by pretreatment with the synthetic auxins 2,4-D, NAA and the gibberellin GA3.

@article{wallstedt_inhibition_2001,
	title = {The inhibition of ammonium uptake in excised birch ({Betula} pendula) roots by batatasin-{III}},
	volume = {113},
	issn = {1399-3054},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2001.1130310.x},
	doi = {10.1034/j.1399-3054.2001.1130310.x},
	abstract = {In northern Sweden, plants growing in association with the clonal dwarf shrub Empetrum hermaphroditum usually exhibit limited growth and are N-depleted. Previous studies suggest that this negative effect by E. hermaphroditum may be explained, at least in part, by the release of phenolic compounds, particularly the dihydrostilbene, batatasin-III from foliage to soil. In the present work, we investigated whether batatasin-III has the potential to interfere with NH4+ uptake in birch (Betula pendula) roots. Excised birch roots were exposed to batatasin-III during brief periods in 15NH4+ solutions, and then analyzed for labeled N. Batatasin-III inhibited N-NH4+ uptake by 28, 89 and 95\% compared with the control, when roots were treated with 0.1, 1.0 and 2.8 mM of batatasin-III, respectively. The effect of 1.0-mM batatasin-III was greater at pH 4.2 than at pH 6.8. In addition, the inhibition of N-NH4+ uptake by batatasin-III was not reversed after rinsing the roots in water and transferring them to a batatasin-III free solution. Furthermore, birch seedlings immersed in a 1.0-mM batatasin-III solution for 2 h, and then replanted in pots with soil, had decreased growth, such that 10 weeks after treatment, the dry mass of both shoots and roots was reduced by 74 and 73\%, respectively, compared with control seedlings. This suggests that a brief exposure to batatasin-III may have a long-term inhibitory effect on whole plant growth. Using plasma membrane vesicles isolated from easily extractable spinach (Spinacia oleracea) leaves, it was found that batatasin-III strongly inhibited proton pumping in isolated plasma membrane vesicles, while it only slightly inhibited ATP hydrolytic activity. The uncoupling of proton pumping from ATP hydrolytic activity suggests that batatasin-III disturbs membrane integrity. This hypothesis was further supported by a greater efflux of ions from birch roots immersed in a batatasin-III solution than from roots in a control solution.},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Physiologia Plantarum},
	author = {Wallstedt, Anna and Sommarin, Marianne and Nilsson, Marie-Charlotte and Munson, Alison D. and Margolis, Hank A.},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1130310.x},
	pages = {368--376},
}

In northern Sweden, plants growing in association with the clonal dwarf shrub Empetrum hermaphroditum usually exhibit limited growth and are N-depleted. Previous studies suggest that this negative effect by E. hermaphroditum may be explained, at least in part, by the release of phenolic compounds, particularly the dihydrostilbene, batatasin-III from foliage to soil. In the present work, we investigated whether batatasin-III has the potential to interfere with NH4+ uptake in birch (Betula pendula) roots. Excised birch roots were exposed to batatasin-III during brief periods in 15NH4+ solutions, and then analyzed for labeled N. Batatasin-III inhibited N-NH4+ uptake by 28, 89 and 95% compared with the control, when roots were treated with 0.1, 1.0 and 2.8 mM of batatasin-III, respectively. The effect of 1.0-mM batatasin-III was greater at pH 4.2 than at pH 6.8. In addition, the inhibition of N-NH4+ uptake by batatasin-III was not reversed after rinsing the roots in water and transferring them to a batatasin-III free solution. Furthermore, birch seedlings immersed in a 1.0-mM batatasin-III solution for 2 h, and then replanted in pots with soil, had decreased growth, such that 10 weeks after treatment, the dry mass of both shoots and roots was reduced by 74 and 73%, respectively, compared with control seedlings. This suggests that a brief exposure to batatasin-III may have a long-term inhibitory effect on whole plant growth. Using plasma membrane vesicles isolated from easily extractable spinach (Spinacia oleracea) leaves, it was found that batatasin-III strongly inhibited proton pumping in isolated plasma membrane vesicles, while it only slightly inhibited ATP hydrolytic activity. The uncoupling of proton pumping from ATP hydrolytic activity suggests that batatasin-III disturbs membrane integrity. This hypothesis was further supported by a greater efflux of ions from birch roots immersed in a batatasin-III solution than from roots in a control solution.

@article{seyedi_cytokinin_2001,
	title = {The cytokinin 2-isopentenyladenine causes partial reversion to skotomorphogenesis and induces formation of prolamellar bodies and protochlorophyllide657 in the lip1 mutant of pea},
	volume = {112},
	issn = {1399-3054},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2001.1120215.x},
	doi = {10.1034/j.1399-3054.2001.1120215.x},
	abstract = {When grown in darkness the photomorphogenic lip1 mutant of pea (Pisum sativum L.) has a slender stem, expanded leaves, prolamellar body (PLB) lacking plastids with the size of chloroplasts and a low level of phytochrome A. The lack of PLBs in a dark-grown material (lip1) created a possibility to further study the regulation of their formation in relation to plant development. Inclusion of a cytokinin, 2-isopentenyladenine (2iP), in a medium supporting growth of the pea seedlings in darkness was found to reduce epicotyl length in the wild type. In lip1 the formation of a slender stem was inhibited and a short epicotyl developed. Furthermore, leaf expansion was inhibited, the plastid size reduced and the formation of PLBs induced. The PLB formation in lip1 was not accompanied by an increase in the amount of protochlorophyllide (Pchlide) or Pchilde oxidoreductase (POR). In the presence of 2iP the level of phytochrome A protein was increased in lip1 and the POR mRNA levels decreased in both lip1 and wild-type plants. The chloroplast characteristic trans-3-hexadecenoate acyl group of phosphatidylglycerol, present in the plastids of dark-grown lip1, was not influenced by 2iP. Thus, not all photomorphogenic processes reacted similarly in the lip1 mutant, but leaf expansion and plastid differentiation, including PLB formation, seemed to be regulated by the same signal transduction chain. Exogenously applied brassinolide could rescue neither dark- nor light-grown defects of the lip1 mutant. Thus, cytokinins but not brassinolides seem to be involved in the regulation of certain characteristic traits of skotomorphogenesis in pea, including plastid development and PLB formation.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Physiologia Plantarum},
	author = {Seyedi, Mahdi and Selstam, Eva and Timko, Michael P. and Sundqvist, Christer},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1120215.x},
	pages = {261--272},
}

When grown in darkness the photomorphogenic lip1 mutant of pea (Pisum sativum L.) has a slender stem, expanded leaves, prolamellar body (PLB) lacking plastids with the size of chloroplasts and a low level of phytochrome A. The lack of PLBs in a dark-grown material (lip1) created a possibility to further study the regulation of their formation in relation to plant development. Inclusion of a cytokinin, 2-isopentenyladenine (2iP), in a medium supporting growth of the pea seedlings in darkness was found to reduce epicotyl length in the wild type. In lip1 the formation of a slender stem was inhibited and a short epicotyl developed. Furthermore, leaf expansion was inhibited, the plastid size reduced and the formation of PLBs induced. The PLB formation in lip1 was not accompanied by an increase in the amount of protochlorophyllide (Pchlide) or Pchilde oxidoreductase (POR). In the presence of 2iP the level of phytochrome A protein was increased in lip1 and the POR mRNA levels decreased in both lip1 and wild-type plants. The chloroplast characteristic trans-3-hexadecenoate acyl group of phosphatidylglycerol, present in the plastids of dark-grown lip1, was not influenced by 2iP. Thus, not all photomorphogenic processes reacted similarly in the lip1 mutant, but leaf expansion and plastid differentiation, including PLB formation, seemed to be regulated by the same signal transduction chain. Exogenously applied brassinolide could rescue neither dark- nor light-grown defects of the lip1 mutant. Thus, cytokinins but not brassinolides seem to be involved in the regulation of certain characteristic traits of skotomorphogenesis in pea, including plastid development and PLB formation.

@article{pocock_susceptibility_2001,
	title = {Susceptibility to low-temperature photoinhibition and the acquisition of freezing tolerance in winter and spring wheat: {The} role of growth temperature and irradiance},
	volume = {113},
	issn = {1399-3054},
	shorttitle = {Susceptibility to low-temperature photoinhibition and the acquisition of freezing tolerance in winter and spring wheat},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2001.1130408.x},
	doi = {10.1034/j.1399-3054.2001.1130408.x},
	abstract = {Five winter and five spring wheat (Triticum aestivum L.) cultivars were grown under either control conditions (20°C/250 photosynthetic photon flux density (PPFD) [μmol m−2 s−1]), high irradiance (20°C/800 PPFD) or at low temperature (either 5°C/250 PPFD or 5°C/50 PPFD). To eliminate any potential bias, the wheat cultivars were arbitrarily chosen without any previous knowledge of their freezing tolerance or photosynthetic competence. We show that the differential susceptibilities to photoinhibition exhibited between spring and winter wheat cultivars, as assessed by chlorophyll fluorescence cannot be explained on the basis of either growth irradiance or low growth temperature per se. The role of excitation pressure is discussed. We assessed the correlation between susceptibility to low-temperature photoinhibition, maximum ribulose 1,5-bisphosphate carboxylase-oxygenase (EC 4.1.1.39) and NADP-dependent malate dehydrogenase (EC 1.1.1.82) activities, chlorophyll and protein concentrations and freezing tolerance determined by electrolyte leakage. Susceptibility to photoinhibition is the only parameter examined that is strongly and negatively correlated with freezing tolerance. We suggest that the assessment of susceptibility to photoinhibition may be a useful predictor of freezing tolerance and field survival of cereals.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Physiologia Plantarum},
	author = {Pocock, Tessa H. and Hurry, Vaughan and Savitch, Leonid V. and Huner, Norman P. A.},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1130408.x},
	pages = {499--506},
}

Five winter and five spring wheat (Triticum aestivum L.) cultivars were grown under either control conditions (20°C/250 photosynthetic photon flux density (PPFD) [μmol m−2 s−1]), high irradiance (20°C/800 PPFD) or at low temperature (either 5°C/250 PPFD or 5°C/50 PPFD). To eliminate any potential bias, the wheat cultivars were arbitrarily chosen without any previous knowledge of their freezing tolerance or photosynthetic competence. We show that the differential susceptibilities to photoinhibition exhibited between spring and winter wheat cultivars, as assessed by chlorophyll fluorescence cannot be explained on the basis of either growth irradiance or low growth temperature per se. The role of excitation pressure is discussed. We assessed the correlation between susceptibility to low-temperature photoinhibition, maximum ribulose 1,5-bisphosphate carboxylase-oxygenase (EC 4.1.1.39) and NADP-dependent malate dehydrogenase (EC 1.1.1.82) activities, chlorophyll and protein concentrations and freezing tolerance determined by electrolyte leakage. Susceptibility to photoinhibition is the only parameter examined that is strongly and negatively correlated with freezing tolerance. We suggest that the assessment of susceptibility to photoinhibition may be a useful predictor of freezing tolerance and field survival of cereals.

@article{ogren_effects_2001,
	title = {Effects of climatic warming on cold hardiness of some northern woody plants assessed from simulation experiments},
	volume = {112},
	issn = {1399-3054},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2001.1120110.x},
	doi = {10.1034/j.1399-3054.2001.1120110.x},
	abstract = {Effects of climatic warming on cold hardiness were investigated for some northern woody plants. In the first experiment, seedlings of Norway spruce (Picea abies [L.] Karst.), Scots pine (Pinus sylvestris L.) and lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) were exposed to naturally fluctuating temperatures averaging −6°C (ambient) and 0°C (elevated) for 16 weeks in midwinter before they were thawed and re-saturated with water. In lodgepole pine, needle sugar concentrations had decreased by 15\%, and the temperature needed to induce 10\% injury to needles in terms of electrolyte leakage had increased by 6°C following treatment to elevated as compared with control temperatures. In contrast, Norway spruce and Scots pine showed no effects. The lack of an effect for Scots pine was ascribed to seedlings containing unusually large energy reserves that buffered respiratory expenditure of sugars. A strong, linear relationship between levels of cold hardiness, assessed by the electrolyte leakage method, and sugars was found when combining data from this and previous, similar experiments. In the second experiment, the evergreen dwarf shrub Empetrum hermaphroditum Hagerup was analysed for leaf cold hardiness, using the electrolyte leakage method, and sugar concentrations in late spring and late autumn during the third year of a warming experiment in a subarctic dwarf shrub community. The objective was to test the hypothesis that warming in the growing season alters hardening/dehardening cycles by increasing soil nitrogen mineralization and plant growth. Data found, however, suggested that cold hardening/dehardening cycles were unaffected by warming.},
	language = {en},
	number = {1},
	urldate = {2021-11-02},
	journal = {Physiologia Plantarum},
	author = {Ögren, Erling},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1120110.x},
	pages = {71--77},
}

Effects of climatic warming on cold hardiness were investigated for some northern woody plants. In the first experiment, seedlings of Norway spruce (Picea abies [L.] Karst.), Scots pine (Pinus sylvestris L.) and lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) were exposed to naturally fluctuating temperatures averaging −6°C (ambient) and 0°C (elevated) for 16 weeks in midwinter before they were thawed and re-saturated with water. In lodgepole pine, needle sugar concentrations had decreased by 15%, and the temperature needed to induce 10% injury to needles in terms of electrolyte leakage had increased by 6°C following treatment to elevated as compared with control temperatures. In contrast, Norway spruce and Scots pine showed no effects. The lack of an effect for Scots pine was ascribed to seedlings containing unusually large energy reserves that buffered respiratory expenditure of sugars. A strong, linear relationship between levels of cold hardiness, assessed by the electrolyte leakage method, and sugars was found when combining data from this and previous, similar experiments. In the second experiment, the evergreen dwarf shrub Empetrum hermaphroditum Hagerup was analysed for leaf cold hardiness, using the electrolyte leakage method, and sugar concentrations in late spring and late autumn during the third year of a warming experiment in a subarctic dwarf shrub community. The objective was to test the hypothesis that warming in the growing season alters hardening/dehardening cycles by increasing soil nitrogen mineralization and plant growth. Data found, however, suggested that cold hardening/dehardening cycles were unaffected by warming.

@article{nasholm_plant_2001,
	title = {Plant acquisition of organic nitrogen in boreal forests},
	volume = {111},
	issn = {1399-3054},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2001.1110401.x},
	doi = {10.1034/j.1399-3054.2001.1110401.x},
	abstract = {Research on plant nitrogen (N) uptake and metabolism has more or less exclusively concerned inorganic N, particularly nitrate. Nevertheless, recent as well as older studies indicate that plants may have access to organic N sources. Laboratory studies have shown that ectomycorrhizal and ericoid mycorrhizal plants can degrade polymeric N and absorb the resulting products. Recent studies have also shown that some non-mycorrhizal plants are able to absorb amino acids. Moreover, amino acid transporters have been shown to be present in both plant roots and in mycorrhizal hyphae. Although both mycorrhizal and non-mycorrhizal plants appear to have a capacity for absorbing a range of organic N compounds, is this capacity realized in the field? Several lines of evidence show that plants are outcompeted by microorganisms for organic N sources. Such studies, however, have not addressed the issue of spatial and temporal separation between plants and microorganisms. Moreover, competition studies have not been able to separate uptake by symbiotic and non-symbiotic microorganisms. Qualitative assessment of organic N uptake by plants has been performed with dual-labelled glycine in several studies. These studies arrive at different conclusions: some indicate that plants do not absorb this organic N source when competing with other organisms in soil, while others conclude that significant fractions of amino acid N are absorbed as intact amino acid. These variable results may reflect species differences in the ability to absorb glycine as well as differences in experimental conditions and analytical techniques. Although theoretical calculations indicate that organic N might add significant amounts of N to plant N uptake, direct quantitative assessment of the fraction of plant N derived from uptake by organic N sources is a challenge for future research.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Physiologia Plantarum},
	author = {Näsholm, Torgny and Persson, Jörgen},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1110401.x},
	pages = {419--426},
}

Research on plant nitrogen (N) uptake and metabolism has more or less exclusively concerned inorganic N, particularly nitrate. Nevertheless, recent as well as older studies indicate that plants may have access to organic N sources. Laboratory studies have shown that ectomycorrhizal and ericoid mycorrhizal plants can degrade polymeric N and absorb the resulting products. Recent studies have also shown that some non-mycorrhizal plants are able to absorb amino acids. Moreover, amino acid transporters have been shown to be present in both plant roots and in mycorrhizal hyphae. Although both mycorrhizal and non-mycorrhizal plants appear to have a capacity for absorbing a range of organic N compounds, is this capacity realized in the field? Several lines of evidence show that plants are outcompeted by microorganisms for organic N sources. Such studies, however, have not addressed the issue of spatial and temporal separation between plants and microorganisms. Moreover, competition studies have not been able to separate uptake by symbiotic and non-symbiotic microorganisms. Qualitative assessment of organic N uptake by plants has been performed with dual-labelled glycine in several studies. These studies arrive at different conclusions: some indicate that plants do not absorb this organic N source when competing with other organisms in soil, while others conclude that significant fractions of amino acid N are absorbed as intact amino acid. These variable results may reflect species differences in the ability to absorb glycine as well as differences in experimental conditions and analytical techniques. Although theoretical calculations indicate that organic N might add significant amounts of N to plant N uptake, direct quantitative assessment of the fraction of plant N derived from uptake by organic N sources is a challenge for future research.

@article{igamberdiev_role_2001,
	title = {The role of photorespiration in redox and energy balance of photosynthetic plant cells: {A} study with a barley mutant deficient in glycine decarboxylase},
	volume = {111},
	issn = {1399-3054},
	shorttitle = {The role of photorespiration in redox and energy balance of photosynthetic plant cells},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2001.1110402.x},
	doi = {10.1034/j.1399-3054.2001.1110402.x},
	abstract = {Protoplasts and mitochondria were isolated from leaves of homozygous barley (Hordeum vulgare L.) mutant deficient in glycine decarboxylase complex (GDC, EC 2.1.2.10) and wild-type plants. The photosynthetic rates of isolated protoplasts from the mutant and wild-type plants under saturating CO2 were similar, but the respiratory rate of the mutant was two-fold higher. Respiration in the mutant plants was much more strongly inhibited by antimycin A than in wild-type plants and a low level of the alternative oxidase protein was found in mitochondria. The activities of NADP- and NAD-dependent malate dehydrogenases were also increased in mutant plants, suggesting an activation of the malate-oxaloacetate exchange for redox transfer between organelles. Mutant plants had elevated activities of NADH- and NADPH-dependent glyoxylate/hydroxypyruvate reductases, which may be involved in oxidizing excess NAD(P)H and the scavenging of glyoxylate. We estimated distribution of pools of adenylates, NAD(H) and NADP(H) between chloroplasts, cytosol and mitochondria. Under photorespiratory conditions, ATP/ADP and NADPH/NADP ratios in the mutant were higher in chloroplasts as compared to wild-type plants. The cytosolic NADH/NAD ratio was increased, whereas the ratio in mitochondria decreased. It is concluded that photorespiration serves as an effective redox transfer mechanism from the chloroplast. Plants with a lowered GDC content are deficient in this mechanism, which leads to over-reduction and over-energization of the chloroplasts.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Physiologia Plantarum},
	author = {Igamberdiev, Abir U. and Bykova, Natalia V. and Lea, Peter J. and Gardeström, Per},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1110402.x},
	pages = {427--438},
}

Protoplasts and mitochondria were isolated from leaves of homozygous barley (Hordeum vulgare L.) mutant deficient in glycine decarboxylase complex (GDC, EC 2.1.2.10) and wild-type plants. The photosynthetic rates of isolated protoplasts from the mutant and wild-type plants under saturating CO2 were similar, but the respiratory rate of the mutant was two-fold higher. Respiration in the mutant plants was much more strongly inhibited by antimycin A than in wild-type plants and a low level of the alternative oxidase protein was found in mitochondria. The activities of NADP- and NAD-dependent malate dehydrogenases were also increased in mutant plants, suggesting an activation of the malate-oxaloacetate exchange for redox transfer between organelles. Mutant plants had elevated activities of NADH- and NADPH-dependent glyoxylate/hydroxypyruvate reductases, which may be involved in oxidizing excess NAD(P)H and the scavenging of glyoxylate. We estimated distribution of pools of adenylates, NAD(H) and NADP(H) between chloroplasts, cytosol and mitochondria. Under photorespiratory conditions, ATP/ADP and NADPH/NADP ratios in the mutant were higher in chloroplasts as compared to wild-type plants. The cytosolic NADH/NAD ratio was increased, whereas the ratio in mitochondria decreased. It is concluded that photorespiration serves as an effective redox transfer mechanism from the chloroplast. Plants with a lowered GDC content are deficient in this mechanism, which leads to over-reduction and over-energization of the chloroplasts.

@article{bykova_involvement_2001,
	title = {Involvement of matrix {NADP} turnover in the oxidation of {NAD}+-linked substrates by pea leaf mitochondria},
	volume = {111},
	issn = {1399-3054},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2001.1110404.x},
	doi = {10.1034/j.1399-3054.2001.1110404.x},
	abstract = {The involvement of the internal rotenone-insensitive NADPH dehydrogenase on the inner surface of the inner mitochondrial membrane [NDin(NADPH)] in the oxidation of strictly NAD+-linked substrates by pea (Pisum sativum L.) leaf mitochondria was measured. As estimated by the inhibition caused by 5 μM diphenyleneiodonium (DPI) in the presence of rotenone to inhibit complex I, the activity of NDin(NADPH) during glycine oxidation (measured both as O2 uptake and as CO2 release) was 40–50 nmol mg−1 protein min−1. No significant activity of NDin(NADPH) could be detected during the oxidation of 2-oxoglutarate, another strictly NAD+-linked substrate; this was possibly due to its relatively low oxidation rate. Control experiments showed that, even at 125 μM, DPI had no effect on the activity of glycine decarboxylase complex (GDC) and lipoamide dehydrogenase. The relative activity of complex I, NDin(NADPH), and NDin(NADH) during glycine oxidation, estimated using rotenone and DPI, differed depending on the pyridine nucleotide supply in the mitochondrial matrix. This was shown by loading the mitochondria with NAD+ and NADP+, both of which were taken up by the organelle. We conclude that the involvement of NADP turnover during glycine oxidation is not due to the direct production of NADPH by GDC but is an indirect result of this process. It probably occurs via the interconversion of NADH to NADPH by the two non-energy-linked transhydrogenase activities recently identified in plant mitochondria.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Physiologia Plantarum},
	author = {Bykova, Natalia V. and Møller, Ian M.},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1110404.x},
	pages = {448--456},
}

The involvement of the internal rotenone-insensitive NADPH dehydrogenase on the inner surface of the inner mitochondrial membrane [NDin(NADPH)] in the oxidation of strictly NAD+-linked substrates by pea (Pisum sativum L.) leaf mitochondria was measured. As estimated by the inhibition caused by 5 μM diphenyleneiodonium (DPI) in the presence of rotenone to inhibit complex I, the activity of NDin(NADPH) during glycine oxidation (measured both as O2 uptake and as CO2 release) was 40–50 nmol mg−1 protein min−1. No significant activity of NDin(NADPH) could be detected during the oxidation of 2-oxoglutarate, another strictly NAD+-linked substrate; this was possibly due to its relatively low oxidation rate. Control experiments showed that, even at 125 μM, DPI had no effect on the activity of glycine decarboxylase complex (GDC) and lipoamide dehydrogenase. The relative activity of complex I, NDin(NADPH), and NDin(NADH) during glycine oxidation, estimated using rotenone and DPI, differed depending on the pyridine nucleotide supply in the mitochondrial matrix. This was shown by loading the mitochondria with NAD+ and NADP+, both of which were taken up by the organelle. We conclude that the involvement of NADP turnover during glycine oxidation is not due to the direct production of NADPH by GDC but is an indirect result of this process. It probably occurs via the interconversion of NADH to NADPH by the two non-energy-linked transhydrogenase activities recently identified in plant mitochondria.

@article{persson_gc-ms_2001,
	title = {A {GC}-{MS} method for determination of amino acid uptake by plants},
	volume = {113},
	issn = {1399-3054},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1034/j.1399-3054.2001.1130308.x},
	doi = {10.1034/j.1399-3054.2001.1130308.x},
	abstract = {In this study, we present a rapid, robust and sensitive method for quantification of plant amino acid uptake using universally (U) (13C, 15N)-labelled amino acids and gas chromatography-mass spectrometry (GC-MS). Amino acids were analysed as their tert-butyldimethylsilyl (tBDMS) derivatives and displayed detection limits in the range 10–100 fmol on column, depending on the amino acid. The technique allows for simultaneous detection and quantification of both unlabelled and isotopically labelled species of amino acids. This makes simple quantification of plant amino acid uptake from an isotopically labelled source possible. The analytical variation was low, concerning total amino acid concentrations (relative standard deviation, rsd, less than 5.3\%) as well as enrichment of U-13C, 15N-labelled glycine (Gly), arginine (Arg) and glutamic acid (Glu) (rsd{\textless}2.1\%). An application of the GC-MS method was conducted on non-mycorrhizal Pinus sylvestris roots supplied with U-13C, 15N-labelled amino acids. Intact, labelled amino acids were traced in root extracts. This provided conclusive evidence of plant root uptake of intact amino acids. Uptake rates of the three amino acids Gly, Glu and Arg in the range 0.5–37.9 μmol g−1 dry weight h−1 were recorded. These rates are comparable with those recorded in earlier studies of amino acid uptake, using other methods, as well as uptake rates measured for nitrate and ammonium.},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Physiologia Plantarum},
	author = {Persson, Jörgen and Näsholm, Torgny},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1399-3054.2001.1130308.x},
	pages = {352--358},
}

In this study, we present a rapid, robust and sensitive method for quantification of plant amino acid uptake using universally (U) (13C, 15N)-labelled amino acids and gas chromatography-mass spectrometry (GC-MS). Amino acids were analysed as their tert-butyldimethylsilyl (tBDMS) derivatives and displayed detection limits in the range 10–100 fmol on column, depending on the amino acid. The technique allows for simultaneous detection and quantification of both unlabelled and isotopically labelled species of amino acids. This makes simple quantification of plant amino acid uptake from an isotopically labelled source possible. The analytical variation was low, concerning total amino acid concentrations (relative standard deviation, rsd, less than 5.3%) as well as enrichment of U-13C, 15N-labelled glycine (Gly), arginine (Arg) and glutamic acid (Glu) (rsd\textless2.1%). An application of the GC-MS method was conducted on non-mycorrhizal Pinus sylvestris roots supplied with U-13C, 15N-labelled amino acids. Intact, labelled amino acids were traced in root extracts. This provided conclusive evidence of plant root uptake of intact amino acids. Uptake rates of the three amino acids Gly, Glu and Arg in the range 0.5–37.9 μmol g−1 dry weight h−1 were recorded. These rates are comparable with those recorded in earlier studies of amino acid uptake, using other methods, as well as uptake rates measured for nitrate and ammonium.

@article{igamberdiev_decarboxylation_2001,
	title = {Decarboxylation of glycine contributes to carbon isotope fractionation in photosynthetic organisms},
	volume = {67},
	issn = {1573-5079},
	url = {https://doi.org/10.1023/A:1010635308668},
	doi = {10.1023/A:1010635308668},
	abstract = {Carbon isotope effects were investigated for the reaction catalyzed by the glycine decarboxylase complex (GDC; EC 2.1.2.10). Mitochondria isolated from leaves of pea (Pisum sativum L.) and spinach (Spinacia oleracea L.) were incubated with glycine, and the CO2 evolved was analyzed for the carbon isotope ratio (δ13C). Within the range of parameters tested (temperature, pH, combination of cofactors NAD+, ADP, pyridoxal 5-phosphate), carbon isotope shifts of CO2 relative to the C1-carboxyl carbon of glycine varied from +14‰ to −7‰. The maximum effect of cofactors was observed for NAD+, the removal of which resulted in a strong 12C enrichment of the CO2 evolved. This indicates the possibility of isotope effects with both positive and negative signs in the GDC reaction. The measurement of δ13C in the leaves of the GDC-deficient barley (Hordeum vulgare L.) mutant (LaPr 87/30) plants indicated that photorespiratory carbon isotope fractionation, opposite in sign when compared to the carbon isotope effect during CO2 photoassimilation, takes place in vivo. Thus the key reaction of photorespiration catalyzed by GDC, together with the key reaction of CO2 fixation catalyzed by ribulose-1,5-bisphosphate carboxylase, both contribute to carbon isotope fractionation in photosynthesis.},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Photosynthesis Research},
	author = {Igamberdiev, Abir U. and Ivlev, Alexander A. and Bykova, Natalia V. and Threlkeld, Charles N. and Lea, Peter J. and Gardeström, Per},
	month = mar,
	year = {2001},
	pages = {177--184},
}

Carbon isotope effects were investigated for the reaction catalyzed by the glycine decarboxylase complex (GDC; EC 2.1.2.10). Mitochondria isolated from leaves of pea (Pisum sativum L.) and spinach (Spinacia oleracea L.) were incubated with glycine, and the CO2 evolved was analyzed for the carbon isotope ratio (δ13C). Within the range of parameters tested (temperature, pH, combination of cofactors NAD+, ADP, pyridoxal 5-phosphate), carbon isotope shifts of CO2 relative to the C1-carboxyl carbon of glycine varied from +14‰ to −7‰. The maximum effect of cofactors was observed for NAD+, the removal of which resulted in a strong 12C enrichment of the CO2 evolved. This indicates the possibility of isotope effects with both positive and negative signs in the GDC reaction. The measurement of δ13C in the leaves of the GDC-deficient barley (Hordeum vulgare L.) mutant (LaPr 87/30) plants indicated that photorespiratory carbon isotope fractionation, opposite in sign when compared to the carbon isotope effect during CO2 photoassimilation, takes place in vivo. Thus the key reaction of photorespiration catalyzed by GDC, together with the key reaction of CO2 fixation catalyzed by ribulose-1,5-bisphosphate carboxylase, both contribute to carbon isotope fractionation in photosynthesis.

@article{nordin_soil_2001,
	title = {Soil nitrogen form and plant nitrogen uptake along a boreal forest productivity gradient},
	volume = {129},
	issn = {1432-1939},
	url = {https://doi.org/10.1007/s004420100698},
	doi = {10.1007/s004420100698},
	abstract = {We present results from a study of soil solution concentrations of ammonium (NH4+), nitrate (NO3–), and amino acid N over one growing season along a local 90-m-long plant productivity gradient in a boreal forest. Three forest types are found along the gradient: an ericaceous dwarf-shrub type between 0 and 40 m, a low-herb type between 40 and 80 m, and a tall-herb type at 90 m. Soil sampling of the mor layer was performed in June, July, August and October in the three forest types. In addition, plant uptake of NH4+, NO3– and the amino acid glycine was investigated. A mixture of the three N forms was injected into the soil; one N form at a time was labeled with 15N, and in the case of glycine also with 13C. In the dwarf-shrub forest, where plant productivity was low, the soil N pool was strongly dominated by amino acid N. There, plants took up more NH4+ than NO3–. Glycine uptake did not differ significantly from either NH4+ or NO3– uptake. Along the gradient, soil concentrations of NH4+ and NO3– increased, as did plant productivity. In the low-herb forest NH4+ comprised a major portion of the soil N pool, and plants took up more NH4+ than NO3– or glycine. In the tall-herb forest, NO3– was as abundant as NH4+, and together these two N forms dominated the soil N pool. Here, plants took up nearly equal amounts of NO3– and NH4+, and this uptake exceeded that of glycine severalfold. Apart from the overall preference for NH4+ that plants exhibited throughout the gradient, the results show a correlation between soil concentrations of amino acids and NO3– and plant preferences for these N forms.},
	language = {en},
	number = {1},
	urldate = {2021-11-02},
	journal = {Oecologia},
	author = {Nordin, Annika and Högberg, Peter and Näsholm, Torgny},
	month = sep,
	year = {2001},
	pages = {125--132},
}

We present results from a study of soil solution concentrations of ammonium (NH4+), nitrate (NO3–), and amino acid N over one growing season along a local 90-m-long plant productivity gradient in a boreal forest. Three forest types are found along the gradient: an ericaceous dwarf-shrub type between 0 and 40 m, a low-herb type between 40 and 80 m, and a tall-herb type at 90 m. Soil sampling of the mor layer was performed in June, July, August and October in the three forest types. In addition, plant uptake of NH4+, NO3– and the amino acid glycine was investigated. A mixture of the three N forms was injected into the soil; one N form at a time was labeled with 15N, and in the case of glycine also with 13C. In the dwarf-shrub forest, where plant productivity was low, the soil N pool was strongly dominated by amino acid N. There, plants took up more NH4+ than NO3–. Glycine uptake did not differ significantly from either NH4+ or NO3– uptake. Along the gradient, soil concentrations of NH4+ and NO3– increased, as did plant productivity. In the low-herb forest NH4+ comprised a major portion of the soil N pool, and plants took up more NH4+ than NO3– or glycine. In the tall-herb forest, NO3– was as abundant as NH4+, and together these two N forms dominated the soil N pool. Here, plants took up nearly equal amounts of NO3– and NH4+, and this uptake exceeded that of glycine severalfold. Apart from the overall preference for NH4+ that plants exhibited throughout the gradient, the results show a correlation between soil concentrations of amino acids and NO3– and plant preferences for these N forms.

@article{westergren_atpip5k1_2001,
	title = {{AtPIP5K1}, an {Arabidopsis} thaliana phosphatidylinositol phosphate kinase, synthesizes {PtdIns}(3,4){P}(2) and {PtdIns}(4,5){P}(2) in vitro and is inhibited by phosphorylation.},
	volume = {359},
	issn = {0264-6021},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1222179/},
	abstract = {PtdIns phosphate kinases (PIPkins), which generate PtdInsP(2) isomers, have been classified into three subfamilies that differ in their substrate specificities. We demonstrate here that the previously identified AtPIP5K1 gene from Arabidopsis thaliana encodes a PIPkin with dual substrate specificity in vitro, capable of phosphorylating PtdIns3P and PtdIns4P to PtdIns(3,4)P(2) and PtdIns(4,5)P(2) respectively. We also show that recombinant AtPIP5K1 is phosphorylated by protein kinase A and a soluble protein kinase from A. thaliana. Phosphorylation of AtPIP5K1 by protein kinase A is accompanied by a 40\% inhibition of its catalytic activity. Full activity is recovered by treating phosphorylated AtPIP5K1 with alkaline phosphatase.},
	number = {Pt 3},
	urldate = {2021-11-02},
	journal = {Biochemical Journal},
	author = {Westergren, T and Dove, S K and Sommarin, M and Pical, C},
	month = nov,
	year = {2001},
	pmid = {11672432},
	pmcid = {PMC1222179},
	pages = {583--589},
}

PtdIns phosphate kinases (PIPkins), which generate PtdInsP(2) isomers, have been classified into three subfamilies that differ in their substrate specificities. We demonstrate here that the previously identified AtPIP5K1 gene from Arabidopsis thaliana encodes a PIPkin with dual substrate specificity in vitro, capable of phosphorylating PtdIns3P and PtdIns4P to PtdIns(3,4)P(2) and PtdIns(4,5)P(2) respectively. We also show that recombinant AtPIP5K1 is phosphorylated by protein kinase A and a soluble protein kinase from A. thaliana. Phosphorylation of AtPIP5K1 by protein kinase A is accompanied by a 40% inhibition of its catalytic activity. Full activity is recovered by treating phosphorylated AtPIP5K1 with alkaline phosphatase.

@article{igamberdiev_implications_2001,
	title = {Implications of adenylate kinase-governed equilibrium of adenylates on contents of free magnesium in plant cells and compartments.},
	volume = {360},
	issn = {0264-6021},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1222221/},
	abstract = {On the basis of the equilibrium of adenylate kinase (AK; EC 2.7.4.3), which interconverts MgATP and free AMP with MgADP and free ADP, an approach has been worked out to calculate concentrations of free magnesium (Mg(2+)), based on concentrations of total ATP, ADP and AMP in plant tissues and in individual subcellular compartments. Based on reported total adenylate contents, [Mg(2+)] in plant tissues and organelles varies significantly depending on light and dark regimes, plant age and developmental stage. In steady-state conditions, [Mg(2+)] in chloroplasts is similar in light and darkness (in the millimolar range), whereas in the cytosol it is very low in the light and increases to about 0.4 mM in darkness. During the dark-to-light transition (photosynthetic induction), the [Mg(2+)] in chloroplasts falls to low values (0.2 mM or less), corresponding to a delay in photosynthetic oxygen evolution. This delay is considered to result from lower activities of Mg-dependent enzymes in the Calvin cycle. In mitochondria, the changes in [Mg(2+)] are similar but smoother. On the other hand, when the transition from light to darkness is considered, an initial increase in [Mg(2+)] occurs in both chloroplasts and mitochondria, which may be of importance for the control of key regulatory enzymes (e.g. mitochondrial malic enzyme and pyruvate dehydrogenase complex) and for processes connected with light-enhanced dark respiration. A rationale is presented for a possible role of [MgATP]/[MgADP] ratio (rather than [ATP(total)]/[ADP(total)]) as an important component of metabolic cellular control. It is postulated that assays of total adenylates may provide an accurate measure of [Mg(2+)] in plant tissues/cells and subcellular compartments, given that the adenylates are equilibrated by AK.},
	number = {Pt 1},
	urldate = {2021-11-02},
	journal = {Biochemical Journal},
	author = {Igamberdiev, A U and Kleczkowski, L A},
	month = nov,
	year = {2001},
	pmid = {11696011},
	pmcid = {PMC1222221},
	pages = {225--231},
}

On the basis of the equilibrium of adenylate kinase (AK; EC 2.7.4.3), which interconverts MgATP and free AMP with MgADP and free ADP, an approach has been worked out to calculate concentrations of free magnesium (Mg(2+)), based on concentrations of total ATP, ADP and AMP in plant tissues and in individual subcellular compartments. Based on reported total adenylate contents, [Mg(2+)] in plant tissues and organelles varies significantly depending on light and dark regimes, plant age and developmental stage. In steady-state conditions, [Mg(2+)] in chloroplasts is similar in light and darkness (in the millimolar range), whereas in the cytosol it is very low in the light and increases to about 0.4 mM in darkness. During the dark-to-light transition (photosynthetic induction), the [Mg(2+)] in chloroplasts falls to low values (0.2 mM or less), corresponding to a delay in photosynthetic oxygen evolution. This delay is considered to result from lower activities of Mg-dependent enzymes in the Calvin cycle. In mitochondria, the changes in [Mg(2+)] are similar but smoother. On the other hand, when the transition from light to darkness is considered, an initial increase in [Mg(2+)] occurs in both chloroplasts and mitochondria, which may be of importance for the control of key regulatory enzymes (e.g. mitochondrial malic enzyme and pyruvate dehydrogenase complex) and for processes connected with light-enhanced dark respiration. A rationale is presented for a possible role of [MgATP]/[MgADP] ratio (rather than [ATP(total)]/[ADP(total)]) as an important component of metabolic cellular control. It is postulated that assays of total adenylates may provide an accurate measure of [Mg(2+)] in plant tissues/cells and subcellular compartments, given that the adenylates are equilibrated by AK.

@article{ciereszko_sucrose_2001,
	title = {Sucrose and light regulation of a cold-inducible {UDP}-glucose pyrophosphorylase gene via a hexokinase-independent and abscisic acid-insensitive pathway in {Arabidopsis}.},
	volume = {354},
	issn = {0264-6021},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1221629/},
	abstract = {UDP-glucose pyrophosphorylase (UGPase) is a key enzyme producing UDP-glucose, which is involved in an array of metabolic pathways concerned with, among other functions, the synthesis of sucrose and cellulose. An Arabidopsis thaliana UGPase-encoding gene, Ugp, was profoundly up-regulated by feeding sucrose to the excised leaves and by an exposure of plants to low temperature (5 degrees C). The UGPase activity and its protein content also increased under conditions of sucrose feeding and exposure to cold. The sucrose effect on Ugp was apparently specific and was mimicked by exposure of dark-adapted leaves to light. Drought and O2 deficiency had some down-regulating effects on expression of Ugp. The sugar-signalling pathway for Ugp regulation was independent of hexokinase, as was found by using transgenic plants with increased and decreased expression of the corresponding gene. Subjecting mutants deficient in abscisic acid (ABA) to cold stress conditions had no effect on Ugp expression profiles. Okadaic acid was a powerful inhibitor of Ugp expression, whereas it up-regulated the gene encoding sucrose synthase (Sus1), indicating distinct transduction pathways in transmitting the sugar signal for the two genes in A. thaliana. We suggest that Ugp gene expression is mediated via a hexokinase-independent and ABA-insensitive pathway that involves an okadaic acid-responsive protein phosphatase. The data point towards Ugp as a possible regulatory entity that is closely involved in the homoeostatic readjustment of plant responses to environmental signals.},
	number = {Pt 1},
	urldate = {2021-11-02},
	journal = {Biochemical Journal},
	author = {Ciereszko, I and Johansson, H and Kleczkowski, L A},
	month = feb,
	year = {2001},
	pmid = {11171080},
	pmcid = {PMC1221629},
	pages = {67--72},
}

UDP-glucose pyrophosphorylase (UGPase) is a key enzyme producing UDP-glucose, which is involved in an array of metabolic pathways concerned with, among other functions, the synthesis of sucrose and cellulose. An Arabidopsis thaliana UGPase-encoding gene, Ugp, was profoundly up-regulated by feeding sucrose to the excised leaves and by an exposure of plants to low temperature (5 degrees C). The UGPase activity and its protein content also increased under conditions of sucrose feeding and exposure to cold. The sucrose effect on Ugp was apparently specific and was mimicked by exposure of dark-adapted leaves to light. Drought and O2 deficiency had some down-regulating effects on expression of Ugp. The sugar-signalling pathway for Ugp regulation was independent of hexokinase, as was found by using transgenic plants with increased and decreased expression of the corresponding gene. Subjecting mutants deficient in abscisic acid (ABA) to cold stress conditions had no effect on Ugp expression profiles. Okadaic acid was a powerful inhibitor of Ugp expression, whereas it up-regulated the gene encoding sucrose synthase (Sus1), indicating distinct transduction pathways in transmitting the sugar signal for the two genes in A. thaliana. We suggest that Ugp gene expression is mediated via a hexokinase-independent and ABA-insensitive pathway that involves an okadaic acid-responsive protein phosphatase. The data point towards Ugp as a possible regulatory entity that is closely involved in the homoeostatic readjustment of plant responses to environmental signals.

@article{gocal_gamyb-like_2001,
	title = {{GAMYB}-like {Genes}, {Flowering}, and {Gibberellin}  {Signaling} in {Arabidopsis}},
	volume = {127},
	issn = {0032-0889},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC133573/},
	abstract = {We have identified three Arabidopsis genes with GAMYB-like activity, AtMYB33, AtMYB65, and AtMYB101, which can substitute for barley (Hordeum vulgare) GAMYB in transactivating the barley α-amylase promoter. We have investigated the relationships between gibberellins (GAs), these GAMYB-like genes, and petiole elongation and flowering of Arabidopsis. Within 1 to 2 d of transferring plants from short- to long-day photoperiods, growth rate and erectness of petioles increased, and there were morphological changes at the shoot apex associated with the transition to flowering. These responses were accompanied by accumulation of GAs in the petioles (GA1 by 11-fold and GA4 by 3-fold), and an increase in expression of AtMYB33 at the shoot apex. Inhibition of GA biosynthesis using paclobutrazol blocked the petiole elongation induced by long days. Causality was suggested by the finding that, with GA treatment, plants flowered in short days, AtMYB33 expression increased at the shoot apex, and the petioles elongated and grew erect. That AtMYB33 may mediate a GA signaling role in flowering was supported by its ability to bind to a specific 8-bp sequence in the promoter of the floral meristem-identity gene, LEAFY, this same sequence being important in the GA response of the LEAFY promoter. One or more of these AtMYB genes may also play a role in the root tip during germination and, later, in stem tissue. These findings extend our earlier studies of GA signaling in the Gramineae to include a dicot species, Arabidopsis, and indicate that GAMYB-like genes may mediate GA signaling in growth and flowering responses.},
	number = {4},
	urldate = {2021-11-02},
	journal = {Plant Physiology},
	author = {Gocal, Gregory F.W. and Sheldon, Candice C. and Gubler, Frank and Moritz, Thomas and Bagnall, David J. and MacMillan, Colleen P. and Li, Song F. and Parish, Roger W. and Dennis, Elizabeth S. and Weigel, Detlef and King, Rod W.},
	month = dec,
	year = {2001},
	pmid = {11743113},
	pmcid = {PMC133573},
	pages = {1682--1693},
}

We have identified three Arabidopsis genes with GAMYB-like activity, AtMYB33, AtMYB65, and AtMYB101, which can substitute for barley (Hordeum vulgare) GAMYB in transactivating the barley α-amylase promoter. We have investigated the relationships between gibberellins (GAs), these GAMYB-like genes, and petiole elongation and flowering of Arabidopsis. Within 1 to 2 d of transferring plants from short- to long-day photoperiods, growth rate and erectness of petioles increased, and there were morphological changes at the shoot apex associated with the transition to flowering. These responses were accompanied by accumulation of GAs in the petioles (GA1 by 11-fold and GA4 by 3-fold), and an increase in expression of AtMYB33 at the shoot apex. Inhibition of GA biosynthesis using paclobutrazol blocked the petiole elongation induced by long days. Causality was suggested by the finding that, with GA treatment, plants flowered in short days, AtMYB33 expression increased at the shoot apex, and the petioles elongated and grew erect. That AtMYB33 may mediate a GA signaling role in flowering was supported by its ability to bind to a specific 8-bp sequence in the promoter of the floral meristem-identity gene, LEAFY, this same sequence being important in the GA response of the LEAFY promoter. One or more of these AtMYB genes may also play a role in the root tip during germination and, later, in stem tissue. These findings extend our earlier studies of GA signaling in the Gramineae to include a dicot species, Arabidopsis, and indicate that GAMYB-like genes may mediate GA signaling in growth and flowering responses.

@article{ganeteg_properties_2001,
	title = {The {Properties} of the {Chlorophyll} a/b-{Binding}  {Proteins} {Lhca2} and {Lhca3} {Studied} in {Vivo} {Using} {Antisense}  {Inhibition}},
	volume = {127},
	issn = {0032-0889},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC117971/},
	abstract = {The specific functions of the light-harvesting proteins Lhca2 and
 Lhca3 were studied in Arabidopsis ecotype Colombia antisense plants in
 which the proteins were individually repressed. The antisense effect
 was specific in each plant, but levels of Lhca proteins other than the
 targeted products were also affected. The contents of Lhca1 and Lhca4
 were unaffected, but Lhca3 (in Lhca2-repressed plants) was almost
 completely depleted, and Lhca2 decreased to about 30\% of wild-type
 levels in Lhca3-repressed plants. This suggests that the Lhca2 and
 Lhca3 proteins are in physical contact with each other and that they
 require each other for stability. Photosystem I fluorescence at 730 nm
 is thought to emanate from pigments bound to Lhca1 and Lhca4. However,
 fluorescence emission and excitation spectra suggest that Lhca2 and
 Lhca3, which fluoresce in vitro at 680 nm, also could contribute to
 far-red fluorescence in vivo. Spectral forms with absorption maxima at
 695 and 715 nm, apparently with emission maxima at 702 and 735 nm,
 respectively, might be associated with Lhca2 and Lhca3.},
	number = {1},
	urldate = {2021-11-02},
	journal = {Plant Physiology},
	author = {Ganeteg, Ulrika and Strand, Åsa and Gustafsson, Petter and Jansson, Stefan},
	month = sep,
	year = {2001},
	pmid = {11553743},
	pmcid = {PMC117971},
	pages = {150--158},
}

The specific functions of the light-harvesting proteins Lhca2 and Lhca3 were studied in Arabidopsis ecotype Colombia antisense plants in which the proteins were individually repressed. The antisense effect was specific in each plant, but levels of Lhca proteins other than the targeted products were also affected. The contents of Lhca1 and Lhca4 were unaffected, but Lhca3 (in Lhca2-repressed plants) was almost completely depleted, and Lhca2 decreased to about 30% of wild-type levels in Lhca3-repressed plants. This suggests that the Lhca2 and Lhca3 proteins are in physical contact with each other and that they require each other for stability. Photosystem I fluorescence at 730 nm is thought to emanate from pigments bound to Lhca1 and Lhca4. However, fluorescence emission and excitation spectra suggest that Lhca2 and Lhca3, which fluoresce in vitro at 680 nm, also could contribute to far-red fluorescence in vivo. Spectral forms with absorption maxima at 695 and 715 nm, apparently with emission maxima at 702 and 735 nm, respectively, might be associated with Lhca2 and Lhca3.

@article{rosenquist_data_2001,
	title = {Data {Mining} the {Arabidopsis} {Genome} {Reveals} {Fifteen} 14-3-3 {Genes}. {Expression} {Is} {Demonstrated} for {Two} out of {Five} {Novel} {Genes}},
	volume = {127},
	url = {https://www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC117970/},
	doi = {10.1104/pp.127.1.142},
	abstract = {In plants, 14-3-3 proteins are key regulators of primary metabolism
 and membrane transport. Although the current dogma states that 14-3-3
 isoforms are not very specific with regard to target proteins, recent
 data suggest that the specificity may be ...},
	language = {en},
	number = {1},
	urldate = {2021-11-02},
	journal = {Plant Physiology},
	author = {Rosenquist, Magnus and Alsterfjord, Magnus and Larsson, Christer and Sommarin, Marianne},
	month = sep,
	year = {2001},
	pmid = {11553742},
	note = {Publisher: Oxford University Press},
	pages = {142},
}

In plants, 14-3-3 proteins are key regulators of primary metabolism and membrane transport. Although the current dogma states that 14-3-3 isoforms are not very specific with regard to target proteins, recent data suggest that the specificity may be ...

@article{ljung_developmental_2001,
	title = {Developmental {Regulation} of {Indole}-3-{Acetic} {Acid} {Turnover} in {Scots} {Pine} {Seedlings1}},
	volume = {125},
	issn = {0032-0889},
	url = {https://doi.org/10.1104/pp.125.1.464},
	doi = {10.1104/pp.125.1.464},
	abstract = {Indole-3-acetic acid (IAA) homeostasis was investigated during seed germination and early seedling growth in Scots pine (Pinus sylvestris). IAA-ester conjugates were initially hydrolyzed in the seed to yield a peak of free IAA prior to initiation of root elongation. Developmental regulation of IAA synthesis was observed, with tryptophan-dependent synthesis being initiated around 4 d and tryptophan-independent synthesis occurring around 7 d after imbibition. Induction of catabolism to yield 2-oxindole-3-acetic acid and irreversible conjugation to indole-3-acetyl-N-aspartic acid was noticed at the same time as de novo synthesis was first detected. As a part of the homeostatic regulation IAA was further metabolized to two new conjugates: glucopyranosyl-1-N-indole-3-acetyl-N-aspartic acid and glucopyranosyl-1-N-indole-3-acetic acid. The initial supply of IAA thus originates from stored pools of IAA-ester conjugates, mainly localized in the embryo itself rather than in the general nutrient storage tissue, the megagametophyte. We have found that de novo synthesis is first induced when the stored pool of conjugated IAA is used up and additional hormone is needed for elongation growth. It is interesting that when de novo synthesis is induced, a distinct induction of catabolic events occurs, indicating that the seedling needs mechanisms to balance synthesis rates for the homeostatic regulation of the IAA pool.},
	number = {1},
	urldate = {2021-11-02},
	journal = {Plant Physiology},
	author = {Ljung, Karin and Östin, Anders and Lioussanne, Laetitia and Sandberg, Göran},
	month = jan,
	year = {2001},
	pages = {464--475},
}

Indole-3-acetic acid (IAA) homeostasis was investigated during seed germination and early seedling growth in Scots pine (Pinus sylvestris). IAA-ester conjugates were initially hydrolyzed in the seed to yield a peak of free IAA prior to initiation of root elongation. Developmental regulation of IAA synthesis was observed, with tryptophan-dependent synthesis being initiated around 4 d and tryptophan-independent synthesis occurring around 7 d after imbibition. Induction of catabolism to yield 2-oxindole-3-acetic acid and irreversible conjugation to indole-3-acetyl-N-aspartic acid was noticed at the same time as de novo synthesis was first detected. As a part of the homeostatic regulation IAA was further metabolized to two new conjugates: glucopyranosyl-1-N-indole-3-acetyl-N-aspartic acid and glucopyranosyl-1-N-indole-3-acetic acid. The initial supply of IAA thus originates from stored pools of IAA-ester conjugates, mainly localized in the embryo itself rather than in the general nutrient storage tissue, the megagametophyte. We have found that de novo synthesis is first induced when the stored pool of conjugated IAA is used up and additional hormone is needed for elongation growth. It is interesting that when de novo synthesis is induced, a distinct induction of catabolic events occurs, indicating that the seedling needs mechanisms to balance synthesis rates for the homeostatic regulation of the IAA pool.

@article{kowalczyk_quantitative_2001,
	title = {Quantitative {Analysis} of {Indole}-3-{Acetic} {Acid} {Metabolites} in {Arabidopsis}},
	volume = {127},
	url = {https://www.ncbi.nlm.nih.gov/sites/ppmc/articles/PMC133588/},
	abstract = {A general gas chromatography/mass spectrometry (MS)-based screen was performed to identify catabolites and conjugates of indole-3-acetic acid (IAA) during vegetative growth of Arabidopsis. This experiment revealed the existence of two new conjugates: ...},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Plant Physiology},
	author = {Kowalczyk, Mariusz and Sandberg, Göran},
	month = dec,
	year = {2001},
	pmid = {11743128},
	note = {Publisher: Oxford University Press},
	pages = {1845},
}

A general gas chromatography/mass spectrometry (MS)-based screen was performed to identify catabolites and conjugates of indole-3-acetic acid (IAA) during vegetative growth of Arabidopsis. This experiment revealed the existence of two new conjugates: ...

@article{king_long-day_2001,
	title = {Long-{Day} {Induction} of {Flowering} in {Lolium} temulentum {Involves} {Sequential} {Increases} in {Specific}  {Gibberellins} at the {Shoot} {Apex}},
	volume = {127},
	issn = {0032-0889},
	url = {https://www.ncbi.nlm.nih.gov/pmc/articles/PMC125097/},
	abstract = {One challenge for plant biology has been to identify floral stimuli at the shoot apex. Using sensitive and specific gas chromatography-mass spectrometry techniques, we have followed changes in gibberellins (GAs) at the shoot apex during long day (LD)-regulated induction of flowering in the grass Lolium temulentum. Two separate roles of GAs in flowering are indicated. First, within 8 h of an inductive LD, i.e. at the time of floral evocation, the GA5 content of the shoot apex doubled to about 120 ng g−1 dry weight. The concentration of applied GA5 required for floral induction of excised apices (R.W. King, C. Blundell, L.T. Evans [1993] Aust J Plant Physiol 20: 337–348) was similar to that in the shoot apex. Leaf-applied [2H4] GA5 was transported intact from the leaf to the shoot apex, flowering being proportional to the amount of GA5 imported. Thus, GA5 could be part of the LD stimulus for floral evocation of L. temulentum or, alternatively, its increase at the shoot apex could follow import of a primary floral stimulus. Later, during inflorescence differentiation and especially after exposure to additional LD, a second GA action was apparent. The content of GA1 and GA4 in the apex increased greatly, whereas GA5 decreased by up to 75\%. GA4 applied during inflorescence differentiation strongly promoted flowering and stem elongation, whereas it was ineffective for earlier floral evocation although it caused stem growth at all times of application. Thus, we conclude that GA1 and GA4 are secondary, late-acting LD stimuli for inflorescence differentiation in L. temulentum.},
	number = {2},
	urldate = {2021-11-02},
	journal = {Plant Physiology},
	author = {King, Rod W. and Moritz, Thomas and Evans, Lloyd T. and Junttila, Olavi and Herlt, Anthony J.},
	month = oct,
	year = {2001},
	pmid = {11598236},
	pmcid = {PMC125097},
	pages = {624--632},
}

One challenge for plant biology has been to identify floral stimuli at the shoot apex. Using sensitive and specific gas chromatography-mass spectrometry techniques, we have followed changes in gibberellins (GAs) at the shoot apex during long day (LD)-regulated induction of flowering in the grass Lolium temulentum. Two separate roles of GAs in flowering are indicated. First, within 8 h of an inductive LD, i.e. at the time of floral evocation, the GA5 content of the shoot apex doubled to about 120 ng g−1 dry weight. The concentration of applied GA5 required for floral induction of excised apices (R.W. King, C. Blundell, L.T. Evans [1993] Aust J Plant Physiol 20: 337–348) was similar to that in the shoot apex. Leaf-applied [2H4] GA5 was transported intact from the leaf to the shoot apex, flowering being proportional to the amount of GA5 imported. Thus, GA5 could be part of the LD stimulus for floral evocation of L. temulentum or, alternatively, its increase at the shoot apex could follow import of a primary floral stimulus. Later, during inflorescence differentiation and especially after exposure to additional LD, a second GA action was apparent. The content of GA1 and GA4 in the apex increased greatly, whereas GA5 decreased by up to 75%. GA4 applied during inflorescence differentiation strongly promoted flowering and stem elongation, whereas it was ineffective for earlier floral evocation although it caused stem growth at all times of application. Thus, we conclude that GA1 and GA4 are secondary, late-acting LD stimuli for inflorescence differentiation in L. temulentum.

@article{mellerowicz_unravelling_2001,
	title = {Unravelling cell wall formation in the woody dicot stem},
	volume = {47},
	issn = {0167-4412},
	abstract = {Populus is presented as a model system for the study of wood formation (xylogenesis). The formation of wood (secondary xylem) is an ordered developmental process involving cell division, cell expansion, secondary wall deposition, lignification and programmed cell death. Because wood is formed in a variable environment and subject to developmental control, xylem cells are produced that differ in size, shape, cell wall structure, texture and composition. Hormones mediate some of the variability observed and control the process of xylogenesis. High-resolution analysis of auxin distribution across cambial region tissues, combined with the analysis of transgenic plants with modified auxin distribution, suggests that auxin provides positional information for the exit of cells from the meristem and probably also for the duration of cell expansion. Poplar sequencing projects have provided access to genes involved in cell wall formation. Genes involved in the biosynthesis of the carbohydrate skeleton of the cell wall are briefly reviewed. Most progress has been made in characterizing pectin methyl esterases that modify pectins in the cambial region. Specific expression patterns have also been found for expansins, xyloglucan endotransglycosylases and cellulose synthases, pointing to their role in wood cell wall formation and modification. Finally, by studying transgenic plants modified in various steps of the monolignol biosynthetic pathway and by localizing the expression of various enzymes, new insight into the lignin biosynthesis in planta has been gained.},
	language = {eng},
	number = {1-2},
	journal = {Plant Molecular Biology},
	author = {Mellerowicz, E. J. and Baucher, M. and Sundberg, B. and Boerjan, W.},
	month = sep,
	year = {2001},
	pmid = {11554475},
	keywords = {Cell Wall, Cellulose, Enzymes, Gene Expression Regulation, Developmental, Gene Expression Regulation, Plant, Lignin, Plant Stems, Trees, Wood},
	pages = {239--274},
}

Populus is presented as a model system for the study of wood formation (xylogenesis). The formation of wood (secondary xylem) is an ordered developmental process involving cell division, cell expansion, secondary wall deposition, lignification and programmed cell death. Because wood is formed in a variable environment and subject to developmental control, xylem cells are produced that differ in size, shape, cell wall structure, texture and composition. Hormones mediate some of the variability observed and control the process of xylogenesis. High-resolution analysis of auxin distribution across cambial region tissues, combined with the analysis of transgenic plants with modified auxin distribution, suggests that auxin provides positional information for the exit of cells from the meristem and probably also for the duration of cell expansion. Poplar sequencing projects have provided access to genes involved in cell wall formation. Genes involved in the biosynthesis of the carbohydrate skeleton of the cell wall are briefly reviewed. Most progress has been made in characterizing pectin methyl esterases that modify pectins in the cambial region. Specific expression patterns have also been found for expansins, xyloglucan endotransglycosylases and cellulose synthases, pointing to their role in wood cell wall formation and modification. Finally, by studying transgenic plants modified in various steps of the monolignol biosynthetic pathway and by localizing the expression of various enzymes, new insight into the lignin biosynthesis in planta has been gained.

@article{halperin_plant_2001,
	title = {Plant mitochondria contain proteolytic and regulatory subunits of the {ATP}-dependent {Clp} protease},
	volume = {45},
	issn = {1573-5028},
	url = {https://doi.org/10.1023/A:1010677220323},
	doi = {10.1023/A:1010677220323},
	abstract = {The proteolytic machinery of plant organelles is largely unknown, although indications so far point to several proteases of bacterial origin. In this study an Arabidopsis thaliana cDNA was isolated that encodes a homologue of bacterial ClpX, a molecular chaperone and regulatory subunit of the ATP-dependent, serine-type Clp protease. Computer analysis of the predicted plant ClpX revealed a putative mitochondrial transit peptide at the N-terminus, as well as overall sequence similarity to other eukaryotic ClpX homologues. Specific polyclonal antibodies were made to the Arabidopsis ClpX protein and used to confirm its localization in plant mitochondria. In addition to ClpX, a ClpP protein located in mitochondria was also identified from the numerous ClpP isomers in Arabidopsis. Localization of this nuclear-encoded protein, termed ClpP2, was determined first by its close sequence similarity to mitochondrial ClpP human, and later experimentally using ClpP2-specific antibodies with isolated plant organellar fractions. In Arabidopsis, transcripts for both clpX and clpP2 genes were detected in various tissues and under different growth conditions, with no significant variation in mRNA level (i.e. 2-fold) for each gene between samples. Using β-casein as a substrate, plant mitochondria were found to possess an ATP-stimulated, serine-type proteolytic activity that could be strongly inhibited by antibodies specific for ClpX or ClpP2, suggesting an active ClpXP protease. The recent discovery of homologous mitochondrial ClpX and ClpP proteins in mammals suggests that this type of protease may be common to multicellular eukaryotes.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {Plant Molecular Biology},
	author = {Halperin, Tami and Zheng, Bo and Itzhaki, Hanan and Clarke, Adrian K. and Adam, Zach},
	month = mar,
	year = {2001},
	pages = {461--468},
}

The proteolytic machinery of plant organelles is largely unknown, although indications so far point to several proteases of bacterial origin. In this study an Arabidopsis thaliana cDNA was isolated that encodes a homologue of bacterial ClpX, a molecular chaperone and regulatory subunit of the ATP-dependent, serine-type Clp protease. Computer analysis of the predicted plant ClpX revealed a putative mitochondrial transit peptide at the N-terminus, as well as overall sequence similarity to other eukaryotic ClpX homologues. Specific polyclonal antibodies were made to the Arabidopsis ClpX protein and used to confirm its localization in plant mitochondria. In addition to ClpX, a ClpP protein located in mitochondria was also identified from the numerous ClpP isomers in Arabidopsis. Localization of this nuclear-encoded protein, termed ClpP2, was determined first by its close sequence similarity to mitochondrial ClpP human, and later experimentally using ClpP2-specific antibodies with isolated plant organellar fractions. In Arabidopsis, transcripts for both clpX and clpP2 genes were detected in various tissues and under different growth conditions, with no significant variation in mRNA level (i.e. 2-fold) for each gene between samples. Using β-casein as a substrate, plant mitochondria were found to possess an ATP-stimulated, serine-type proteolytic activity that could be strongly inhibited by antibodies specific for ClpX or ClpP2, suggesting an active ClpXP protease. The recent discovery of homologous mitochondrial ClpX and ClpP proteins in mammals suggests that this type of protease may be common to multicellular eukaryotes.

@article{parry_novel_2001,
	title = {Novel auxin transport inhibitors phenocopy the auxin influx carrier mutation aux1},
	volume = {25},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2001.00970.x},
	doi = {10.1046/j.1365-313x.2001.00970.x},
	abstract = {The hormone auxin is transported in plants through the combined actions of diffusion and specific auxin influx and efflux carriers. In contrast to auxin efflux, for which there are well documented inhibitors, understanding the developmental roles of carrier-mediated auxin influx has been hampered by the absence of specific competitive inhibitors. However, several molecules that inhibit auxin influx in cultured cells have been described recently. The physiological effects of two of these novel influx carrier inhibitors, 1-naphthoxyacetic acid (1-NOA) and 3-chloro-4-hydroxyphenylacetic acid (CHPAA), have been investigated in intact seedlings and tissue segments using classical and new auxin transport bioassays. Both molecules do disrupt root gravitropism, which is a developmental process requiring rapid auxin redistribution. Furthermore, the auxin-insensitive and agravitropic root-growth characteristics of aux1 plants were phenocopied by 1-NOA and CHPAA. Similarly, the agravitropic phenotype of inhibitor-treated seedlings was rescued by the auxin 1-naphthaleneacetic acid, but not by 2,4-dichlorophenoxyacetic acid, again resembling the relative abilities of these two auxins to rescue the phenotype of aux1. Further investigations have shown that none of these compounds block polar auxin transport, and that CHPAA exhibits some auxin-like activity at high concentrations. Whilst results indicate that 1-NOA and CHPAA represent useful tools for physiological studies addressing the role of auxin influx in planta, 1-NOA is likely to prove the more useful of the two compounds.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {The Plant Journal},
	author = {Parry, Geraint and Delbarre, Alain and Marchant, Alan and Swarup, Ranjan and Napier, Richard and Perrot-Rechenmann, Catherine and Bennett, Malcolm J.},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2001.00970.x},
	keywords = {AUX1, Arabidopsis, auxin influx carrier, auxin transport, auxin transport inhibitors, root gravitropism},
	pages = {399--406},
}

The hormone auxin is transported in plants through the combined actions of diffusion and specific auxin influx and efflux carriers. In contrast to auxin efflux, for which there are well documented inhibitors, understanding the developmental roles of carrier-mediated auxin influx has been hampered by the absence of specific competitive inhibitors. However, several molecules that inhibit auxin influx in cultured cells have been described recently. The physiological effects of two of these novel influx carrier inhibitors, 1-naphthoxyacetic acid (1-NOA) and 3-chloro-4-hydroxyphenylacetic acid (CHPAA), have been investigated in intact seedlings and tissue segments using classical and new auxin transport bioassays. Both molecules do disrupt root gravitropism, which is a developmental process requiring rapid auxin redistribution. Furthermore, the auxin-insensitive and agravitropic root-growth characteristics of aux1 plants were phenocopied by 1-NOA and CHPAA. Similarly, the agravitropic phenotype of inhibitor-treated seedlings was rescued by the auxin 1-naphthaleneacetic acid, but not by 2,4-dichlorophenoxyacetic acid, again resembling the relative abilities of these two auxins to rescue the phenotype of aux1. Further investigations have shown that none of these compounds block polar auxin transport, and that CHPAA exhibits some auxin-like activity at high concentrations. Whilst results indicate that 1-NOA and CHPAA represent useful tools for physiological studies addressing the role of auxin influx in planta, 1-NOA is likely to prove the more useful of the two compounds.

@article{fischer-iglesias_auxin_2001,
	title = {Auxin distribution and transport during embryonic pattern formation in wheat},
	volume = {26},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2001.01013.x},
	doi = {10.1046/j.1365-313x.2001.01013.x},
	abstract = {Inhibitors of auxin polar transport disrupt normal embryogenesis and thus specific spatial auxin distribution due to auxin movement may be important in establishing embryonic pattern formation in plants. In the present study, the distribution of the photoaffinity labeling agent tritiated 5-azidoindole-3-acetic acid ([3H],5-N3IAA), an analog of indole-3-acetic acid (IAA), was visualized in zygotic wheat (Triticum aestivum L.) embryos grown in vitro and in planta, and used to deduce auxin transport pathways in these embryos. This study provides the first direct evidence that the distribution of auxin, here [3H],5-N3IAA, is heterogeneous and changes during embryo development. In particular, the shift from radial to bilateral symmetry was correlated with a redistribution of [3H],5-N3IAA in the embryo. Furthermore, in bilaterally symmetrical embryos, that is, embryos in the late transition stage or older, the localization of [3H],5-N3IAA was altered by N-1-naphthylphthalamic acid, a specific inhibitor of auxin polar transport. No significant effect was observed in radially symmetrical embryos, that is, globular embryos, or very early transition embryos. Thus, the shift from radial to bilateral symmetry is associated with the onset of active, directed auxin transport involved in auxin redistribution. A change in the distribution of [3H],5-N3IAA was also observed in morphologically abnormal embryos induced on media supplemented with auxin or auxin polar transport inhibitors. By means of a microscale technique, free IAA concentration was measured in in vitro- and in planta-grown embryos and was found to increase during development. Therefore, IAA may be synthesized or released from conjugates in bilaterally symmetrical embryos, although import from surrounding tissues cannot be excluded.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {The Plant Journal},
	author = {Fischer-Iglesias, Christiane and Sundberg, Björn and Neuhaus, Gunther and Jones, Alan Munte},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2001.01013.x},
	keywords = {auxin localization, embryonic pattern formation, free IAA concentration, photoaffinity labeling, polar auxin transport, wheat},
	pages = {115--129},
}

Inhibitors of auxin polar transport disrupt normal embryogenesis and thus specific spatial auxin distribution due to auxin movement may be important in establishing embryonic pattern formation in plants. In the present study, the distribution of the photoaffinity labeling agent tritiated 5-azidoindole-3-acetic acid ([3H],5-N3IAA), an analog of indole-3-acetic acid (IAA), was visualized in zygotic wheat (Triticum aestivum L.) embryos grown in vitro and in planta, and used to deduce auxin transport pathways in these embryos. This study provides the first direct evidence that the distribution of auxin, here [3H],5-N3IAA, is heterogeneous and changes during embryo development. In particular, the shift from radial to bilateral symmetry was correlated with a redistribution of [3H],5-N3IAA in the embryo. Furthermore, in bilaterally symmetrical embryos, that is, embryos in the late transition stage or older, the localization of [3H],5-N3IAA was altered by N-1-naphthylphthalamic acid, a specific inhibitor of auxin polar transport. No significant effect was observed in radially symmetrical embryos, that is, globular embryos, or very early transition embryos. Thus, the shift from radial to bilateral symmetry is associated with the onset of active, directed auxin transport involved in auxin redistribution. A change in the distribution of [3H],5-N3IAA was also observed in morphologically abnormal embryos induced on media supplemented with auxin or auxin polar transport inhibitors. By means of a microscale technique, free IAA concentration was measured in in vitro- and in planta-grown embryos and was found to increase during development. Therefore, IAA may be synthesized or released from conjugates in bilaterally symmetrical embryos, although import from surrounding tissues cannot be excluded.

@article{ljung_sites_2001,
	title = {Sites and homeostatic control of auxin biosynthesis in {Arabidopsis} during vegetative growth},
	volume = {28},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313X.2001.01173.x},
	doi = {10.1046/j.1365-313X.2001.01173.x},
	abstract = {The distribution and biosynthesis of indole-3-acetic acid (IAA) was investigated during early plant development in Arabidopsis. The youngest leaves analysed, less than 0.5 mm in length, contained 250 pg mg−1 of IAA and also exhibited the highest relative capacity to synthesize this hormone. A decrease of nearly one hundred-fold in IAA content occurred as the young leaves expanded to their full size, and this was accompanied by a clear shift in both pool size and IAA synthesis capacity. The correlation between high IAA content and intense cell division was further verified in tobacco leaves, where a detailed analysis revealed that dividing mesophyll tissue contained ten-fold higher IAA levels than tissue growing solely by elongation. We demonstrated that all parts of the young Arabidopsis plant can potentially contribute to the auxin needed for growth and development, as not only young leaves, but also all other parts of the plant such as cotyledons, expanding leaves and root tissues have the capacity to synthesize IAA de novo. We also observed that naphthylphthalamic acid (NPA) treatment induced tissue-dependent feedback inhibition of IAA biosynthesis in expanding leaves and cotyledons, but intriguingly not in young leaves or in the root system. This observation supports the hypothesis that there is a sophisticated tissue-specific regulatory mechanism for auxin biosynthesis. Finally, a strict requirement for maintaining the pool sizes of IAA was revealed as reductions in leaf expansion followed both decreases and increases in the IAA levels in developing leaves. This indicates that leaves are not only important sources for IAA synthesis, but that normal leaf expansion depends on rigorous control of IAA homeostasis.},
	language = {en},
	number = {4},
	urldate = {2021-11-02},
	journal = {The Plant Journal},
	author = {Ljung, Karin and Bhalerao, Rishikesh P. and Sandberg, Göran},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313X.2001.01173.x},
	keywords = {auxin, distribution and biosynthesis, feedback inhibition, indole-3-acetic acid, leaf expansion, naphthylphthalamic acid},
	pages = {465--474},
}

The distribution and biosynthesis of indole-3-acetic acid (IAA) was investigated during early plant development in Arabidopsis. The youngest leaves analysed, less than 0.5 mm in length, contained 250 pg mg−1 of IAA and also exhibited the highest relative capacity to synthesize this hormone. A decrease of nearly one hundred-fold in IAA content occurred as the young leaves expanded to their full size, and this was accompanied by a clear shift in both pool size and IAA synthesis capacity. The correlation between high IAA content and intense cell division was further verified in tobacco leaves, where a detailed analysis revealed that dividing mesophyll tissue contained ten-fold higher IAA levels than tissue growing solely by elongation. We demonstrated that all parts of the young Arabidopsis plant can potentially contribute to the auxin needed for growth and development, as not only young leaves, but also all other parts of the plant such as cotyledons, expanding leaves and root tissues have the capacity to synthesize IAA de novo. We also observed that naphthylphthalamic acid (NPA) treatment induced tissue-dependent feedback inhibition of IAA biosynthesis in expanding leaves and cotyledons, but intriguingly not in young leaves or in the root system. This observation supports the hypothesis that there is a sophisticated tissue-specific regulatory mechanism for auxin biosynthesis. Finally, a strict requirement for maintaining the pool sizes of IAA was revealed as reductions in leaf expansion followed both decreases and increases in the IAA levels in developing leaves. This indicates that leaves are not only important sources for IAA synthesis, but that normal leaf expansion depends on rigorous control of IAA homeostasis.

@article{hertzberg_cdna_2001,
	title = {{cDNA} microarray analysis of small plant tissue samples using a {cDNA} tag target amplification protocol},
	volume = {25},
	issn = {1365-313X},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-313x.2001.00972.x},
	doi = {10.1046/j.1365-313x.2001.00972.x},
	abstract = {Microarray technology is becoming an important comprehensive tool to study gene expression in plants. However, the use of this technology is limited by the large amount of sample tissue needed for microarray analysis. Generally, 50–200 µg of total RNA and 1–2 µg of mRNA is required for each hybridisation, which is equivalent to 50–100 mg of plant tissue. This requirement for large amounts of starting material severely constrains the use of microarrays for transcript profiling in specific tissues and cell types during plant development. Here we report on a robust and reliable target amplification method that enables transcript profiling from sub-mg amounts of plant tissue. Using 0.1 µg of total RNA we show that twofold expression differences are possible to distinguish with 99\% confidence. We also demonstrate the application of this method in an analysis of secondary phloem development in hybrid aspen using defined tissue sections, corresponding to 2–4 cell layers with a fresh weight of ∼0.5 mg.},
	language = {en},
	number = {5},
	urldate = {2021-11-02},
	journal = {The Plant Journal},
	author = {Hertzberg, Magnus and Sievertzon, Maria and Aspeborg, Henrik and Nilsson, Peter and Sandberg, Göran and Lundeberg, Joakim},
	year = {2001},
	note = {\_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1365-313x.2001.00972.x},
	keywords = {PCR, cDNA-amplification, microarray, phloem development, populus tremula x tremuloides, transcript profiling},
	pages = {585--591},
}

Microarray technology is becoming an important comprehensive tool to study gene expression in plants. However, the use of this technology is limited by the large amount of sample tissue needed for microarray analysis. Generally, 50–200 µg of total RNA and 1–2 µg of mRNA is required for each hybridisation, which is equivalent to 50–100 mg of plant tissue. This requirement for large amounts of starting material severely constrains the use of microarrays for transcript profiling in specific tissues and cell types during plant development. Here we report on a robust and reliable target amplification method that enables transcript profiling from sub-mg amounts of plant tissue. Using 0.1 µg of total RNA we show that twofold expression differences are possible to distinguish with 99% confidence. We also demonstrate the application of this method in an analysis of secondary phloem development in hybrid aspen using defined tissue sections, corresponding to 2–4 cell layers with a fresh weight of ∼0.5 mg.

@article{schmid_ricinosomes_2001,
	title = {The ricinosomes of senescing plant tissue bud from the endoplasmic reticulum},
	volume = {98},
	copyright = {Copyright © 2001, The National Academy of Sciences},
	issn = {0027-8424, 1091-6490},
	url = {https://www.pnas.org/content/98/9/5353},
	doi = {10.1073/pnas.061038298},
	abstract = {The ricinosome (synonym, precursor protease vesicle) is a novel organelle, found so far exclusively in plant cells. Electron microscopic studies suggest that it buds off from the endoplasmic reticulum in senescing tissues. Biochemical support for this unusual origin now comes from the composition of the purified organelle, which contains large amounts of a 45-kDa cysteine endoprotease precursor with a C-terminal KDEL motif and the endoplasmic reticulum lumen residents BiP (binding protein) and protein disulfide isomerase. Western blot analysis, peptide sequencing, and mass spectrometry demonstrate retention of KDEL in the protease proform. Acidification of isolated ricinosomes causes castor bean cysteine endopeptidase activation, with cleavage of the N-terminal propeptide and the C-terminal KDEL motif. We propose that ricinosomes accumulate during senescence by programmed cell death and are activated by release of protons from acidic vacuoles.},
	language = {en},
	number = {9},
	urldate = {2021-11-02},
	journal = {Proceedings of the National Academy of Sciences},
	author = {Schmid, Markus and Simpson, David J. and Sarioglu, Hakan and Lottspeich, Friedrich and Gietl, Christine},
	month = apr,
	year = {2001},
	pmid = {11296243},
	note = {Publisher: National Academy of Sciences
Section: Biological Sciences},
	keywords = {Ricinus communis, papain-type KDEL peptidase},
	pages = {5353--5358},
}

The ricinosome (synonym, precursor protease vesicle) is a novel organelle, found so far exclusively in plant cells. Electron microscopic studies suggest that it buds off from the endoplasmic reticulum in senescing tissues. Biochemical support for this unusual origin now comes from the composition of the purified organelle, which contains large amounts of a 45-kDa cysteine endoprotease precursor with a C-terminal KDEL motif and the endoplasmic reticulum lumen residents BiP (binding protein) and protein disulfide isomerase. Western blot analysis, peptide sequencing, and mass spectrometry demonstrate retention of KDEL in the protease proform. Acidification of isolated ricinosomes causes castor bean cysteine endopeptidase activation, with cleavage of the N-terminal propeptide and the C-terminal KDEL motif. We propose that ricinosomes accumulate during senescence by programmed cell death and are activated by release of protons from acidic vacuoles.

@incollection{pesquet_xylem_2001,
	series = {Molecular {Breeding} of {Woody} {Plants}},
	title = {Xylem {Formation} and {Lignification} in {Trees} and {Model} {Species}},
	volume = {18},
	url = {https://www.sciencedirect.com/science/article/pii/S0921042301800514},
	abstract = {Laccases (EC 1.10.3.2) are blue copper oxidases that are found in a large variety of living organisms including bacteria, fungi, insects and plants 1., 2., 3.. To date their role in these organisms has not yet been clearly established. In higher plants, based on their capacity to oxidize monolignols in vitro and localization at the cell wall, laccases are considered candidate enzymes in the ultimate step in lignification. In order to provide functional evidence to support or refute this hypothesis, four lines of antisense poplars, each corresponding to a different gene, were obtained. Although none of the lines exhibited significant differences in either lignin content or composition, one line, lac3AS, is characterized by a two to three-fold increase in soluble phenolics and perturbations in cell adhesion of xylem fibers. The fact that several laccases from Zinnia (8 out of the 9 obtained) are heavily induced at the onset of lignification during the formation of tracheary elements (TEs) further suggest then involvement of laccases in secondary cell wall formation. In order to make a quantitative leap in our understanding of lignification and vascular development, we are currently developing two strategies that will lead to the identification of new genes involved in these plant–specific processes. Firstly, we have constructed a “late xylogenesis” cDNA library by suppression subtractive hybridization (SSH) from differentiating TEs of Zinnia. Approximately 75\% of the 800 clones obtained appear to be differentially expressed during TE formation. A limited number of differentially expressed clones were randomly chosen and sequenced. Among them, known molecular markers of late xylogenesis including a cysteine protease and an endonuclease were identified, demonstrating the quality of the library. Massive sequencing and the determination of detailed expression profiles of these cDNAs are now underway. Secondly, we have screened T-DNA tagged Arabidopsis mutants (Versailles collection) for atypical vascular patterns in floral stems. One of these mutants, hca, for high cambial activity, is characterized by the formation of a continuous ring of vascular tissue as opposed to the discrete vascular bundles typically observed in Arabidopsis. The identification of the gene responsible for this phenotype is now underway.},
	language = {en},
	urldate = {2021-11-02},
	booktitle = {Progress in {Biotechnology}},
	publisher = {Elsevier},
	author = {Pesquet, Edouard and Pichon, Magalie and Pineau, Christophe and Ranocha, Philippe and Digonnet, Catherine and Jauneau, Alain and Boudet, Alain M. and Fukuda, Hiroo and Demura, Taku and Goffner, Deborah},
	editor = {Morohoshi, Noriyuki and Komamine, Atsushi},
	month = jan,
	year = {2001},
	doi = {10.1016/S0921-0423(01)80051-4},
	keywords = {Lignin, antisense poplar, laccase, mutants, subtractive library},
	pages = {11--18},
}

Laccases (EC 1.10.3.2) are blue copper oxidases that are found in a large variety of living organisms including bacteria, fungi, insects and plants 1., 2., 3.. To date their role in these organisms has not yet been clearly established. In higher plants, based on their capacity to oxidize monolignols in vitro and localization at the cell wall, laccases are considered candidate enzymes in the ultimate step in lignification. In order to provide functional evidence to support or refute this hypothesis, four lines of antisense poplars, each corresponding to a different gene, were obtained. Although none of the lines exhibited significant differences in either lignin content or composition, one line, lac3AS, is characterized by a two to three-fold increase in soluble phenolics and perturbations in cell adhesion of xylem fibers. The fact that several laccases from Zinnia (8 out of the 9 obtained) are heavily induced at the onset of lignification during the formation of tracheary elements (TEs) further suggest then involvement of laccases in secondary cell wall formation. In order to make a quantitative leap in our understanding of lignification and vascular development, we are currently developing two strategies that will lead to the identification of new genes involved in these plant–specific processes. Firstly, we have constructed a “late xylogenesis” cDNA library by suppression subtractive hybridization (SSH) from differentiating TEs of Zinnia. Approximately 75% of the 800 clones obtained appear to be differentially expressed during TE formation. A limited number of differentially expressed clones were randomly chosen and sequenced. Among them, known molecular markers of late xylogenesis including a cysteine protease and an endonuclease were identified, demonstrating the quality of the library. Massive sequencing and the determination of detailed expression profiles of these cDNAs are now underway. Secondly, we have screened T-DNA tagged Arabidopsis mutants (Versailles collection) for atypical vascular patterns in floral stems. One of these mutants, hca, for high cambial activity, is characterized by the formation of a continuous ring of vascular tissue as opposed to the discrete vascular bundles typically observed in Arabidopsis. The identification of the gene responsible for this phenotype is now underway.

@article{wu_variation_2001,
	title = {Variation on reaction norm in lodgepole pine natural populations},
	volume = {103},
	issn = {1432-2242},
	url = {https://doi.org/10.1007/s001220100540},
	doi = {10.1007/s001220100540},
	abstract = {Variations on the norm of reaction among ten natural lodgepole pine populations sampled from three lodgepole pine subspecies (Pinus contorta ssp. contorta, ssp. latifolia and ssp. murrayana) were studied by using 20 year heights measured in 57 provenance test sites across interior British Columbia (B.C.). There were significant population by site interactions. Concurrent joint regression and the AMMI model were used to dissect these population by environmental interactions. Joint regression analysis indicated that three populations (from the northwest) had a negative linear regression coefficient with environmental deviation, three (from central and southeast sites) had a positive regression coefficient and four (from the southwest) had a zero regression coefficient. The AMMI model revealed a similar pattern of reaction norm among the ten populations. But the three significant IPCA axes, which captured twice as much of the G × E sum of squares than joint regression, were more effective in separating the ten populations and associating their performance with the climate of test sites and their origin. The variation patterns of reaction norm in lodgepole pine populations demonstrated that adaptation of lodgepole pine natural populations to the various physical environments, at sub-species as well as at population level, was due largely to a balance between selection for high growth potential in less severe environments and selection for high cold hardiness in severe environments.},
	language = {en},
	number = {2},
	urldate = {2021-11-02},
	journal = {Theoretical and Applied Genetics},
	author = {Wu, H. X. and Ying, C. C.},
	month = aug,
	year = {2001},
	pages = {331--345},
}

Variations on the norm of reaction among ten natural lodgepole pine populations sampled from three lodgepole pine subspecies (Pinus contorta ssp. contorta, ssp. latifolia and ssp. murrayana) were studied by using 20 year heights measured in 57 provenance test sites across interior British Columbia (B.C.). There were significant population by site interactions. Concurrent joint regression and the AMMI model were used to dissect these population by environmental interactions. Joint regression analysis indicated that three populations (from the northwest) had a negative linear regression coefficient with environmental deviation, three (from central and southeast sites) had a positive regression coefficient and four (from the southwest) had a zero regression coefficient. The AMMI model revealed a similar pattern of reaction norm among the ten populations. But the three significant IPCA axes, which captured twice as much of the G × E sum of squares than joint regression, were more effective in separating the ten populations and associating their performance with the climate of test sites and their origin. The variation patterns of reaction norm in lodgepole pine populations demonstrated that adaptation of lodgepole pine natural populations to the various physical environments, at sub-species as well as at population level, was due largely to a balance between selection for high growth potential in less severe environments and selection for high cold hardiness in severe environments.

@article{wu_reciprocal_2001,
	title = {Reciprocal, maternal and non-maternal effects in radiata pine diallel mating experiment on four {Australia} sites},
	volume = {8},
	abstract = {To investigate the importance of the reciprocal effect in a series of Australia-wide radiata pine 6 × 6 half-diallel matings, one diallel mating set was deliberately mated to include reciprocal crosses. At age ten and a half, five traits (DBH, stem straightness, branch angle, branch size and cluster whorl number) were assessed at four sites, and the reciprocal effects were estimated and partitioned into the maternal and non-maternal components. General combined ability was significant (P {\textless} 0.001) for DBH, stem straightness, branch angle, and branch size while specific combined ability was significant (P {\textless} 0.039) for stem straightness, branch angle, and cluster number. The overall reciprocal effect was significant for branch angle only; however, there were reciprocal effects in individual pair-crosses for DBH, branch size and cluster number. A partitioning of these significant reciprocal effects suggests either maternal (e.g. cytoplasmic DNA effect) and non-maternal effects (e.g. interaction effect between nuclear and cytoplasmic DNA) or purely non-maternal interaction may be the causes of the reciprocal effects. The observed overall weak reciprocal effect in this experiment indicates that (1) reciprocal mating could be used if it is easier or cheaper to use a particular parent as female for commercial production in radiata pine, and (2) half-diallel mating is suitable for the mating design to estimate genetic parameters and variance components, and pooling reciprocal crosses into a half-diallel mating structure should be acceptable for the standard half-diallel genetic analysis.},
	journal = {Forest Genetics},
	author = {Wu, H.X. and Matheson, A.C.},
	month = sep,
	year = {2001},
	pages = {205--212},
}

To investigate the importance of the reciprocal effect in a series of Australia-wide radiata pine 6 × 6 half-diallel matings, one diallel mating set was deliberately mated to include reciprocal crosses. At age ten and a half, five traits (DBH, stem straightness, branch angle, branch size and cluster whorl number) were assessed at four sites, and the reciprocal effects were estimated and partitioned into the maternal and non-maternal components. General combined ability was significant (P \textless 0.001) for DBH, stem straightness, branch angle, and branch size while specific combined ability was significant (P \textless 0.039) for stem straightness, branch angle, and cluster number. The overall reciprocal effect was significant for branch angle only; however, there were reciprocal effects in individual pair-crosses for DBH, branch size and cluster number. A partitioning of these significant reciprocal effects suggests either maternal (e.g. cytoplasmic DNA effect) and non-maternal effects (e.g. interaction effect between nuclear and cytoplasmic DNA) or purely non-maternal interaction may be the causes of the reciprocal effects. The observed overall weak reciprocal effect in this experiment indicates that (1) reciprocal mating could be used if it is easier or cheaper to use a particular parent as female for commercial production in radiata pine, and (2) half-diallel mating is suitable for the mating design to estimate genetic parameters and variance components, and pooling reciprocal crosses into a half-diallel mating structure should be acceptable for the standard half-diallel genetic analysis.

@article{ericsson_genetic_2001,
	title = {Genetic correlations of heartwood extractives in {Pinus} sylvestris progeny tests},
	volume = {8},
	abstract = {Estimates of additive genetic correlations (r,) between wood extractive concentrations in heartwood of Scots pine (Pinus sylvestris L.) at two sites in northern Sweden were found to be high, on average, while their ge-netic correlations with tree growth were less clear. In a full-sib 25-year-old progeny test, r, was estimated to be about 0.7 between pinosylvins and resin acid contents, and about 0.9 between specific compounds within the pinosylvin and resin acid groups. The saturated fatty acid contents were also correlated with pinosylvins and resi? acid contents (r, = 0.4 to 0.8), while genetic correlations involving unsaturated fatty acids were low-er, and less distinctly expressed. Concentrations of sterols were negatively correlated (r, = -0.6) with those of other wood extractives. Similar patterns were found, confirming these trends, in another, 44-year old, full-sib progeny test. The generally high heritabilities recorded for production of fungitoxic substances (pinosylvins and resin acids), and the apparent absence of negative genetic correlations with tree growth or heartwood for-mation, suggest that each of the studied traits could be considered for inclusion in commercial tree breeding programs.},
	journal = {Forest Genetics},
	author = {Ericsson, Tore and Fries, Anders and Gref, Rolf},
	month = may,
	year = {2001},
}

Estimates of additive genetic correlations (r,) between wood extractive concentrations in heartwood of Scots pine (Pinus sylvestris L.) at two sites in northern Sweden were found to be high, on average, while their ge-netic correlations with tree growth were less clear. In a full-sib 25-year-old progeny test, r, was estimated to be about 0.7 between pinosylvins and resin acid contents, and about 0.9 between specific compounds within the pinosylvin and resin acid groups. The saturated fatty acid contents were also correlated with pinosylvins and resi? acid contents (r, = 0.4 to 0.8), while genetic correlations involving unsaturated fatty acids were low-er, and less distinctly expressed. Concentrations of sterols were negatively correlated (r, = -0.6) with those of other wood extractives. Similar patterns were found, confirming these trends, in another, 44-year old, full-sib progeny test. The generally high heritabilities recorded for production of fungitoxic substances (pinosylvins and resin acids), and the apparent absence of negative genetic correlations with tree growth or heartwood for-mation, suggest that each of the studied traits could be considered for inclusion in commercial tree breeding programs.

@article{hanson_sugar-dependent_2001,
	title = {Sugar-dependent alterations in cotyledon and leaf development in transgenic plants expressing the {HDZhdip} gene {ATHB13}},
	volume = {45},
	issn = {1573-5028},
	url = {https://doi.org/10.1023/A:1006464907710},
	doi = {10.1023/A:1006464907710},
	abstract = {ATHB13 is a new member of the homeodomain leucine zipper (HDZip) transcription factor family of Arabidopsis thaliana. Constitutive high-level expression of the ATHB13 cDNA in transgenic plants results in altered development of cotyledons and leaves, specifically in plants grown on media containing metabolizable sugars. Cotyledons and leaves of sugar-grown transgenic plants are more narrow and the junction between the petiole and the leaf blade less distinct, as compared to the wild type. High-level expression of ATHB13 affects cotyledon shape by inhibiting lateral expansion of epidermal cells in sugar-treated seedlings. Experiments with non-metabolizable sugars indicate that the alteration in leaf shape in the ATHB13 transgenics is mediated by sucrose sensing. ATHB13 further affects a subset of the gene expression responses of the wild-type plant to sugars. The expression of genes encoding β-amylase and vegetative storage protein is induced to higher levels in response to sucrose in the transgenic plants as compared to the wild type. The expression of other sugar-regulated genes examined is unaffected by ATHB13. These data suggest that ATHB13 may be a component of the sucrose-signalling pathway, active close to the targets of the signal transduction.},
	language = {en},
	number = {3},
	urldate = {2021-11-02},
	journal = {Plant Molecular Biology},
	author = {Hanson, Johannes and Johannesson, Henrik and Engström, Peter},
	month = feb,
	year = {2001},
	pages = {247--262},
}

ATHB13 is a new member of the homeodomain leucine zipper (HDZip) transcription factor family of Arabidopsis thaliana. Constitutive high-level expression of the ATHB13 cDNA in transgenic plants results in altered development of cotyledons and leaves, specifically in plants grown on media containing metabolizable sugars. Cotyledons and leaves of sugar-grown transgenic plants are more narrow and the junction between the petiole and the leaf blade less distinct, as compared to the wild type. High-level expression of ATHB13 affects cotyledon shape by inhibiting lateral expansion of epidermal cells in sugar-treated seedlings. Experiments with non-metabolizable sugars indicate that the alteration in leaf shape in the ATHB13 transgenics is mediated by sucrose sensing. ATHB13 further affects a subset of the gene expression responses of the wild-type plant to sugars. The expression of genes encoding β-amylase and vegetative storage protein is induced to higher levels in response to sucrose in the transgenic plants as compared to the wild type. The expression of other sugar-regulated genes examined is unaffected by ATHB13. These data suggest that ATHB13 may be a component of the sucrose-signalling pathway, active close to the targets of the signal transduction.