... when the temperature is raised. The effect of DCMU on the traces was to increase the amplitude of step J with the concurrent decline of stepI, and to retard the rise to Fm. With dPQ, the J ... FEBShave attributed both of the two latter phases to the reduction of the acceptor side of PSII [9,12,13], or morespecifically to the reduction of two distinct plastoqui-none (PQ) pools [8,14,15]. ... correspond to the end of the J–I phase [8,28,29]. It is likely that the emergence of a peak for I in the FI curves depends on the relative amplitude and rate constant of the J–Iphase compared to the...