Investigation of electron transport in the photosynthetic systems of higher plants by the EPR method-I. Influence of the pre-history of illumination on the kinetics of the photo-induced redox conversions of P700

After adaptation of the leaves in the dark (2-4 min) the kinetics of the appearance of the EPR signal assumes a multi-phasic character: an initial jump is followed by a stage of slower rise. The "memory" of the system for the action of light of 600 nm is manifest in the form of a delay in the rise of the EPR I signal under the influence of light of 707 nm and persists in the dark for several minutes. If the light of 600 nm is switched on against the background of light of 707 nm at least 2-4 min after switching it off in the preceding cycle, a non monotonie transitional process with an overburst is observed.