Fig. 1. Cytochrome f redox changes in continuous light as measured by absorbance changes. (A, C, E and G) State 1. (B, D, F and H) State 2. (A and B) wild type; (C and D) stt7; (E and F) bf4; (G and H) A-AUU strain. Symbols: squares, no inhibitors; circles, DCMU 10 µM; triangles, DBMIB 2 µM. Other conditions are described in Methods. Upward and downward arrows indicate the switch on and off of the actinic light, respectively. A decrease of absorbance corresponds to oxidation of cytochrome f. Traces were normalized on the amplitude of a PSI-driven charge separation signal measured at 515 nm.