Reduction kinetics of the photo‐oxidized chlorophyll a⁺II in the nanosecond range

The 688 nm absorption changes (Δ A 688 ), indicating the photochemical turnover of chlorophyll a II (Chl a II ) have been investigated under repetitive laser flash excitation conditions in spinach chlorplasts. It was found that under steady state conditions about 50–60% of the photo‐oxidized primary donor of Photosystem II (PS II), Chl a + II , becomes re‐reduced with a biphasic kinetics in the nanosecond time scale with half‐life times of about 50 ns and 400 ns. The remaining Chl a + II becomes re‐reduced in the microsecond range.