Flash fluorescence induction:: a novel method to study regulation of Photosystem II

We demonstrate that arrays of light-emitting diodes can be used to generate single-turnover flashes of light that saturate Q(A) reduction in green algae. The fast version of a double-modulation fluorometer can measure induction during a single-turnover saturating flash (flash fluorescence induction). The method allows the effective antenna size, antenna heterogeneity and connectivity of Photosystem II to be measured without poisoning the organism with herbicide that blocks Q(A)(-) reoxidation. Using the same instrument, we have also measured the functional heterogeneity of Photosystem II by the fluorescence transient related to the flash-induced advancement of S-states in the oxygen-envolving complex. (C) 1999 Elsevier Science S.A. All rights reserved.