AN APPRAISAL OF PHOTOSYNTHETIC FLUORESCENCE KINETICS AS A PROBE OF PLANT FUNCTION

The origin of fluorescence in plant and cyanobacteria is examined, in steady state and as fast fluorescence decays. The majority of fluoresc ence arises from Photosystem 2 (PS2), and the influence of energy tran sfer kinetic changes, state transitions and PS2 alpha and beta on the fluorescence decays is reviewed. The theoretically simpler system of P S1 is also considered, together with the light harvesting complex II. That most models have arisen following studies on isolated PS1, PS2 an d light harvesting complexes can be considered a problem in relating t he results to in vivo situations. The most widely used fluorescence pr obe is the Kautsky effect of fluorescence induction, and few workers h ave measured fast kinetics, spectra and fluorescence induction. Exampl es are given where more than one type of study has been made.