Study on the photosynthetic function decline induced by hydrogen peroxide in wheat leaves

Effects of the different concentrations H2O2 on the photosynthetic function in wheat(Triticum aestivum L.)leaf were studied.The results showed that photosynthesis was little influenced by 1 mmol·L-1 H2O2 treatment,and was inhibited in varying degrees by 10,100,200 mmol·L-1 H2O2 treatment in vivo and in vitro leaves,and photosynthetic rate and chlorophyll content declined.Chloroplast ultrastructure in the mesophyll cells of wheat were observed and there was a little change by 10mmol·L-1 H2O2 treatment,and a remarkable breakdown of granal stacks and disorganized thylakoid membranes were revealed by 200 mmol·L-1 H2O2 treatment.Large subunit(LSU) and small subunit(SSU) of Ribulose-1,5-bisphosphate carboxylase / oxygenase(Rubisco) and Rubisco carboxylation activity had a little change in 20 mmol·L-1 H2O2 stress.With 100 mmol·L-1 H2O2 treatment LSU and SSU of Rubisco degraded obviously and the carboxylase activity was weak.The results provided strong evidence that H2O2 induced the photosynthetic function decline of wheat leaves.