The Influence of Stress Analyzed By The Emitted Fluorescence Changes

The chlorophyll (Chl) fluorescence signatures of leaves have been widely applied as non-invasive techniques for the in vivo analysis of plant stress. The Chl fluorescence provides ample information on the photosynthetic apparatus as first discovered by Kautsky. Various ratios of the Chl fluorescence determined from the induction kinetics can be used as indicators of the stress effect to the photosynthetic apparatus. The high resolution multi-colour Chl fluorescence imaging techniques for whole leaves have been developed over the last years. These techniques offer the new possibility to study the distribution and patchiness of fluorescence signatures over the whole leaf area. The chlorophyll fluorescence induction kinetics (Kautsky effect) of pre- darkened leaves (30 min) was measured using the FluorCam 700MF imaging system (Photon Systems Instrument). The images of the measured Chl fluorescence intensity were obtained on false colour, whereby blue is the lowest (zero) and red the highest fluorescence. The images of various Chl fluorescence ratios were obtained by pixel to pixel arithmetic operations performed by FluorCam software. Efficiency of photosynthetic apparatus of analyzed endemic plants grown in different environmental stress conditions was evaluated via chlorophyll fluorescence imaging during induction kinetics and the fluorescence ratios which describe the photosynthetic light processes and quantum conversion of light.