H_2O_2诱导小麦叶片光合功能衰退的研究

采用不同浓度的H2O2处理小麦,研究H2O2对小麦叶片光合功能的影响.结果表明:1 mmol.L-1H2O2对小麦叶片光合作用基本无影响,10、100、200 mmol.L-1H2O2对小麦离体和连体叶片的光合作用均有不同程度的抑制作用,表现为光合速率、叶绿素含量下降.叶绿体超微结构显示10 mmol.L-1H2O2对其有影响,200 mmol.L-1H2O2处理后基粒明显破坏,类囊体膜无序.核酮糖-1,5-二磷酸羧化酶加氧酶(Rubisco)大小亚基和羧化活性在20 mmol.L-1H2O2逆境下变化小,100 mmol.L-1H2O2处理,Rubisco大小亚基降解明显,羧化活性微弱.说明H2O2诱导小麦叶片光合功能衰退.

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

Effects of the different concentrations H_2O_2 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) H_2O_2 treatment, and was inhibited in varying degrees by 10, 100, 200 mmol·L~(-1) H_2O_2 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) H_2O_2 treatment, and a remarkable breakdown of granal stacks and disorganized thylakoid membranes were revealed by 200 mmol·L~(-1) H_2O_2 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) H_2O_2 stress. With 100 mmol·L~(-1) H_2O_2 treatment LSU and SSU of Rubisco degraded obviously and the carboxylase activity was weak. The results provided strong evidence that H_2O_2 induced the photosynthetic function decline of wheat leaves.