Sulfite Inhibition of Photosystem II in Illuminated Spinach Leaves

PS II activity (dichlorophenolindophenol photoreduction) inchloroplasts isolated from sulfite-treated spinach leaves inlight was inhibited but not in darkness. Sulfite treatment decreasedthe variable part of fluorescence induction and the fluorescenceintensities of emissions at 685 and 694 nm at 77K, but it hadno effect when sulfite was administered together with DCMU.These results indicate that sulfite inactivates the PS II reactioncenter when electron transport takes place. (Received August 5, 1983; Accepted November 25, 1983)