Pulse-amplitude modulated (PAM) fluorometry is one of the most common techniques used to study the photosynthetic electron transfer chain in different physiological conditions. The Dual-PAM-100 measuring system (Heinz Walz GmbH; www.walz.com) is suited for Photosystem II analysis via chlorophyll fluorescence and the state of Photosystem I can be accessed via dual-wavelength P700 absorbance measurements. Chlorophyll fluorescence and P700 pulse-modulated measurements are synchronized for minimal mutual disturbance, allowing the simultaneous assessment of different photosynthesis parameters via fluorescence and absorbance measurements. The light-induced formation of the trans-thylakoid proton gradient, ΔpH can be evaluated via 9-amino acridine fluorescence.
The Dual-PAM-100 provides many measuring routines for optimal assessment of photosynthetic parameters. All essential light sources are integrated into the system: red or blue fluorescence excitation light, P700 measuring light, single turnover saturating flashes, actinic light and far-red light. All of these can be switched within 2.5 µs time resolution. A wide range of measuring light frequencies (1 Hz to 400 kHz) ensure the recording of fast kinetics. The measuring head with integrated light sources is compact and easy to handle.
For a review on Chl fluorescence see: Maxwell K. and Johnson G., J. Exp. Bot. (2000) 51, 659–668, Kalaji H. et al, Photosynth Res (2017) 132, 13–66, Kramer D et al, Photosynth. Res. (2004) 79, 209-218.
Location: room B3.44.49
Fluorescence imaging system Speedzen 200 (JBeamBio) designed for measurements of in vivo chlorophyll fluorescence, resolved in time and space. The sensor is a Hamamatsu Orca Flash 4.0 LT video camera that can deliver 30 frames per second. The low emission values are represented by cold colours, while strong fluorescence is represented by warm colours, creating the false-colour scale for the fluorescence image.
The device uses the principle of "dark pulse". The actinic light is cut just before the measurements of chlorophyll fluorescence and re-established immediately after the image is taken. A red filter is placed in front of the camera to separate the blue excitation light from the red fluorescence light. An infrared light source is used to adjust the focus of the lens by illuminating the scene with non-actinic light (740 nm). The camera focal plane is 90 mm below the light sources. The accompanying software offers many possibilities for graphical representation.
More information in this publication: 2009 Johnson et al. Photosynth Res 102, 85.
Location: room B3-38-51
Handy FluorCam (Photon System Instruments, psi.cz) is a portable device designed for time-resolved chlorophyll fluorescence imaging of leaves, small plants or algal colonies. It consists of a CCD camera and four fixed LED panels that provide measuring pulses, actinic illumination and saturating flashes. Handy FluorCam generates images of fluorescence transients induced by actinic light or saturating flashes and presents them using a false-colour scale. The FluorCam was used for instance in Wang L. et al, PNAS (2016) 113, 3792-3800.
Location: B3.38.51