水分胁迫诱导玉米叶片质外体产生H2O2机理

摘要

通过组织化学染色、电镜观察、酶活性分析对水分胁迫诱导玉米叶片质外体产生H2O2进行了研究.结果表明:水分胁迫能够诱导玉米叶片内源ABA的积累,ABA参与了水分胁迫诱导的玉米叶片H2O2的产生,质膜NADPH氧化酶、细胞壁过氧化物酶(POD)以及质外体多胺氧化酶(PAO)是水分胁迫诱导玉米细胞在质外体产生H2O2的来源,其中质膜NADPH氧化酶是主要来源；内源ABA的积累参与了水分胁迫激活的质膜NADPH氧化酶、细胞壁POD和质外体PAO活性的提高.研究认为,水分胁迫诱导玉米细胞在质外体产生H2O2可能是由于水分胁迫下内源ABA的积累通过激活质膜NADPH氧化酶、细胞壁POD以及质外体PAO的活性而实现的.%ln maize (Zeamays L. ) cells,the source of apoplast hydrogen peroxide (H2O2) induced by water stress ( - 0. 7 Mpa induced by polyethylene glycol) have been proposed,using different inhibitors for each enzymes,the histochemical and cytochemical observation and the analysis of the eyzeme activities. The results indicated that, the plasma membrane (PM) oxidase,cell wall peroxidase (POD) and the polyamine oxidases (PAO) take part in the H2O2 accumulation induced by water stress. Among them,NADPH oxi-dase could be the major soure of the apoplastic H2O2 production induced by water stress. The activities of PM NADPH oxidase,cell wall POD and apoplast PAO were all decreased significantly compared to that in the tugstate-pretreated maize plants,which indicated that ABA accumulation induced by water stress participated in the activation of the three enzymes. The results suggested that ABA accumulation induced by water stress can lead to significant increases in apoplast H2O2 accumulation through up-regulating the activities of the PM NADPH oxidases,cell wall POD and apoplast PAO.