[Kinetics of dark reduction of P700 centers in photosynthesis]

Relationship between the rate of dark fall of ESR I signal in the chloroplasts and light intensity 710 nm was studied. It is shown that the kinetics of the signal drop at sufficiently high levels of intensity is a biphase one. The fast phase (2 sec) disappears in the presence of an inhibitor of noncyclic electron transfer. It is concluded that the kinetics of electron transport is not described within the concept of the linear chain of electron carriers and a suggestion is put forward concerning a possible mechanism of this process which depends on the participation of plastoquinone in electron transport.