... The delayed fluorescence of chlorophyll (DF) is an informative characteristic of the backward electron transfer in the reaction centers (RC) as well as of the functional activity of the photosynthetic apparatus (PSA) in vivo and in vitro under various physical and chemical factors (Hauvax, Lannoye, 1985; Rubin et al., ... Predominant bleaching of the long-wavelength fraction of chlorophyll provides evidence that oxidative reactions are located close to the reaction center of PSI. ...