Using fluorescence methods, it was shown that the energy transfer from flavin to protochlorophyilide (PChlide) 655/650 and to the products of its photoconversion (chlorophyllide) couid be observed up to the completion of the Shibata shift. The changes in fluorescence spectra of NADPH and flavins, accompanying the PChlide 655/650 photoreduction at 77 K, allow to assume the participation of NADPH and flavins in the primary photoreactions of chlorophyllide formation.