The currently accepted model of primary energy conversion in the plant photosystems must be substantially modernized.
According to the current model of primary events in plants, electronic excitations generated in antenna chlorophylls (Chl) by the light rapidly migrate within vast Chl ensembles, reach the reaction centres (RCs) and initiate the primary photoreactions of electron transfer from the RC special pairs (P700 and P680 in plant photosystems). A minor portion of electronic excitations is lost en route, in particular, via fluorescence of Chl a. A number of fluorescence parameters in vivo had been reliably established in many independent studies. Based on these parameters, the author calculated a dimensionless value, the ratio of fluorescence yields emitted by PS-2 and PS-1 Chl a ensembles. The ratio proved to differ 5-10 times from that obtained in experiments. Such a divergence seems to indicate an internal discrepancy in the currently used model. The author proposes a substantial modernization of the model by introducing a new subpicosecond state for RCs, which precedes the primary reaction of electron transfer from the RC special pairs.
Borisov
A Y
AY
Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia. ayb@photosyn.genebee.msu.su
D004579:Electron Transport; D004583:Electrons; D004734:Energy Metabolism; D008954:Models, Biological; D008956:Models, Chemical; D010788:Photosynthesis; D018521:Plant Physiological Phenomena