Regulation of electron-transport pathways in cells of Chlamydomonas reinhardtii under stress conditions

The kinetics of interactions between electron-transport pathways in the thylakoid membrane was examined. A mathematical model was proposed to describe the kinetics of redox transitions in photosystem II, proton concentration changes in the chloroplast stroma, and the plastoquinone pool reduction due to photosynthetic and chlororespiratory pathways. A kinetic mechanism is considered that redirects electron flows between photosynthetic and chlororespiratory pathways in response to the increased NADPH content under mineral deficiency. According to the simulation model, the electron transport flows via different routes are switched over in a stepwise manner. The results of numerical simulations are qualitatively consistent with experimental data for Chlamydomonas reinhardtii cells subjected to mineral deprivation.