Effect of hydrogen peroxide on the fluorescence and the G550 absorption change of spinach chloroplast fragments

摘要

Effects of H2O2on the transient phase of fluorescence and the light-induced absorption change of C550 in the presence of ferricyanide were studied in spinach chloroplast fragments at room temperature. In the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), the parameter of the variable fluorescence, work integral, was increased by the addition of H2O2and the rate of its recovery in the dark was decreased. The steady-state fluorescence yield was decreased by H2O2. Essentially the same results were obtained in the absence of ferricyanide.In the presence of DCMU, H2O2decreased the steady-state absorption change of C550 and inhibited its reoxidation in the dark. The same effects were observed when H2O2was added to chloroplast fragments in the presence of DCMU and carbonyl cyanidem-chlorophenylhydrazone. From these data we concluded that the fluorescence quencher Q and C550 are not identical.