Thermoluminescence in plants.

Recently considerable progress has been achieved in the elucidation of the origin of thermoluminescence in chloroplasts. The assignment of 2 ot the thermoluminescence bands, peaking at around +5°C (Q or D band) and +30°C (B band), to the recombination of charges, originating from the oxidized species of the oxygen evolving complex (the so-called S states) and to the reduced primary and secondary quinone acceptors QA and QB, respectively, has aided in the investigation of reactions involving both the electron donor and acceptor sides of photosystem II. In this paper we review recent thermoluminescence results concerning the deactivation of S states, temperature and pH dependence of S state transitions, and the activity of the water oxidizing system after removal of Cl-, manganese or the 33 kDa protein. Reports on the use of thermoluminescence in investigations on the sites of action of herbicides and redox changes of QB conferred by herbicide resistance are also discussed. The effect of pH, bicarbonate, and Acceleration of Deactivation Reaction of enzyme "Y" (ADRY) reagents on the photosystem II reactions are presented in the light of thermoluminescence observations. Further possible applications of thermoluminescence promising better understanding of the photosynthetic processes are suggested. [ABSTRACT FROM AUTHOR]