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. 2008 Oct 17;283(42):28380–28391. doi: 10.1074/jbc.M710465200

FIGURE 6.

FIGURE 6.

The effects of heat stress on PS II activity in the thylakoids and PS II membranes and on release of manganese from PS II. The samples were incubated at 40 °C for the periods indicated either under aerobic or anaerobic conditions. A, oxygen evolving activity in the thylakoids (closed circles) and PS II membranes (open circles). The samples were incubated at 40 °C under the aerobic conditions. 100% of the oxygen evolving activity corresponds to 91 μmol of O2 evolved mg-1 chlorophyll h-1 with the thylakoids and 311 μmol of O2 evolved mg-1 chlorophyll h-1 with the PS II membranes. The antenna size of the PS II preparation was assumed to be 270 chlorophylls, based on Ref. 21. B, Fv/Fm of chlorophyll fluorescence in the thylakoids under the aerobic (closed circles) or anaerobic (open circles) conditions. The 100% values under the aerobic and anaerobic conditions are 0.68 and 0.64, respectively. C, Fv/Fm of chlorophyll fluorescence in the PS II membranes under aerobic (closed circles) and anaerobic (open circles) conditions. The 100% values under the aerobic and anaerobic conditions correspond to 0.75 and 0.67, respectively. D, the content of manganese in the PS II membranes under the aerobic (closed circles) or anaerobic (open circles) conditions. All the data are the average of three measurements ± S.D.