Mathematical Modeling of Photosynthetic Electron Transport Chain Considering Spatial Heterogeneity of the Thylakoid Membrane

New mathematical model of photosynthetic apparatus in the thylakoid membrane is proposed. The main feature of the model is the simultaneous consideration of all processes of electron transport, including electron transfer within the reaction centers of protein complexes and diffusion of mobile electron carriers. The model describes main reactions of linear and cyclic electron transport and spatial heteroheneity of thylakoid membrane. Using the model, we calculate theoretical curves of cholorophyll $a$ fluorescence and ${}_\Delta820$ signal intensity time dependence at the first second after illumination of dark-adapted leaves. Calculated curves are in a good agree with experimental data, including the data obtained in the presence of photosynthetic inhibitors and electron acceptors. These results show that three main stages of chlorophyll a fluorescence induction curve reflect the consequent reduction of acceptor side of photosystem II, plastoquinone pool and farthest electron carriers, including the photosystem I and ferredoxin. The new approach for description of spatial structure of the membrane is suggested. Using this approach, we model the system by one-dimensional segment with asymmetrically distributed components of electron transport chain.