ABA诱导玉米叶质外体H2O2积累的机制

通过组织化学染色和电镜观察并结合酶活性分析表明，ABA可通过诱导玉米（Zea mays L、）叶片质膜NADPH氧化酶、细胞壁POD及质外体PAO活性的升高，使其质外体产生H2O2；其中质膜NADPH氧化酶起主要作用。

The Mechanism of ABA-induced Apoplastic H2O2 Accumulation in Maize Leaves

In maize(Zea mays L.)cells,the sourcesof apoplast hydrogen peroxide(H2O2)induced byabscisic acid(ABA)has been proposed.His-tochemical and cytochemical localization of ABA-induced H2O2 production in leaves of maize wasexamined,using 3,3-diaminobenzidine(DAB)andcerium chloride(CeCl3)staining respectively.Pre-treatment with two different inhibitors for eachenzymes,with diphenylene iodonium(DPI)andimidazole against NADPH oxidase,NaCN andNaN3 against peroxidases(POD),and quinacrineand guazatine against polyamine oxidases(PAO),reduced H2O2 accumulation induced by ABA.Among them,NADPH oxidase inhibitors arrestedthe production of apoplastic H2O2 most strongly(Figs.1,2).Further studies showed that exogenousABA treatment could enhance the activities ofplasma membrane(PM)NADPH oxidase,cell wallPOD and apoplast PAO significantly.Moreover,the activity of PM NADPH oxidase kept increas-ing before 1.5 h,while the other two enzymes be-gan to decrease at 0.5 h within 2 h by ABA treat-ment(Fig.3).The results suggest that exogenousABA treatment can lead to significant increases inH2O2 accumulation in apoplast through up-regu-lating the activities of the PM NADPH oxidases,cell wall POD and apoplast PAO,of which the firstone plays a central role in ABA-induced apoplasticH2O2 accumulation.