ИСТИНА • РИНЦ
Based on up-to-date physicochemical data, a complete kinetic model of the catalytic cycle of photosystem II (PS II) for higher green plants was constructed. In compliance with the time hierarchy of photosynthetic stages, the model was reduced in order to describe only processes occurring on the millisecond time scale. In terms of the model, chlorophyll fluorescence induction curves at different values of model parameters were calculated. The fluorescence intensity was determined from an equation for calculating the concentrations of PS II fluorescence states and their dependence on the components of the electrochemical potential across the tylacoid membrane. The proposed model, which considers only processes occurring within PS II, cannot describe some features of the ascending branch of the chlorophyll fluorescence induction curve. It was found that the steady-state level of the fluorescence intensity may nonmonotonically depend on the transmembrane electric potential.
A kinetic model was developed for generation and utilization of the transmembrane electrochemical proton gradient in primary photosynthetic processes in chloroplasts. The model gives a detailed description of the catalytic cycles in photosysterns I and II, the cytochrome bf-complex, ATP synthesis, and passive leakage of H+, K+, and Cl- through the thylakoid membrane. Account is taken of the dependence of the electron transport rate on the transmembrane potential. The model was tested for consistency with the experimental data on the fast phase of chlorophyll fluorescence induction under different light intensities (high to low). The composition of the fluorescence response was analyzed for each illumination level.