FDMR OF CHLOROPHYLL TRIPLETS IN INTEGRATED PARTICLES AND ISOLATED REACTION CENTERS OF PHOTOSYSTEM .2. IDENTIFICATION OF P680 TRIPLET

Fluorescence detected magnetic resonance (FDMR) of various chlorophyll a triplets in PS II large particles was studied with the aim of ident ifying the nature of the different components underlying the complex l ine shape of the signals. The latter are deconvoluted into sums of Gau ssians in different experimental conditions, and the charge recombinat ion triplet is unequivocally identified as the source of two lines wit h negative signs at 722.5 and 992 MHz (\D\ = 0.0286 cm(-1), \E\ = 0.00 43 cm(-1)). The origin of the other triplet signals from the integrate d particles is discussed in terms of functional antenna components and products from alteration of the native environment of pigments. FDMR signals also arise from isolated reaction centre complexes and are all to be attributed to different triplet populations of the primary elec tron donor P680. The results are compared with those obtained by other authors on ADMR. The heterogeneity of P680 pigments in D1D2-cyt-b(559 ) complexes is shown to arise during preparation procedures.