Kinetics of light-induced redox transients of photosystem I reaction center P₇₀₀ in leaves of C₃ and C₄ plants

The light-induced changes in the kinetics of the oxidation of photosystem I reaction center P₇₀₀ in leaves of C₃ and C₄ plants, depending on the time of leaf adaptation to dark before the illumination were studied. The EPR 1 signal from oxidized centers P⁺₇₀₀ was used to monitor the kinetics of P₇₀₀ redox transients. Similar dependences of the light-induced changes in the kinetics of P₇₀₀ versus the adaptation time were observed in leaves of three kinds of plants: bean, orange and maize. These data suggest that the deactivation of the Calvin cycle enzymes, which occurs 1-3 min after ceasing the illumination, is the main factor that causes the retardation of the light-induced oxidation of P₇₀₀.