玉米灰斑病抗性机制中活性氧代谢的作用

The role of reactive oxygen species metabolism in resistance mechanism to gray leaf spot in maize

研究了玉米灰斑病菌侵染四个抗病和感病的玉米品种时,叶片内部活性氧代谢酶及细胞过氧化产物含量的动力学变化。结果表明,抗、感病品种的SOD、CAT及POD酶活性在病菌侵染后都变化显著,抗病品种各酶活性变化幅度比感病品种大。叶片内过氧化产物MDA含量则相反,抗病品种沈试29在接种第13天时叶片MDA含量只为18.46nmol/g,而感病品种铁单9为23.14nmol/g,抗病品种比感病品种增加幅度小。说明活性氧代谢在植物抗病机制中起着重要作用,抗病品种对活性氧代谢的酶调节能力强,病菌侵染后细胞过氧化程度低,在病菌侵染时活性氧清除酶活性最大增加值与发病程度呈显著正相关。

The changes in the activities of ROs (reactive oxygen species) enzymes and the production of peroxidatic reaction in four maize cultivars were studied. The result showed that the activities of SOD, CAT and POD in resistant and susceptible cultivars had all increased at first of the inoculation but then decreased. The range of the changes in resistant cultivars was larger than those in the susceptible. The MDA content, however, displayed a reversed trend. The content of MDA was 18.46 nmol/g at the 13th day after inoculation in the resistant cultivar Shenshi 29 while it was 23.14 nmol/g in the susceptible cultivar Tiedan 9, for example. It showed that the reactive oxygen species play an important role in resistance of maize and the ability of regulation of ROs in resistance cultivars is stronger than that in the susceptible cultivars. The maximal increased values in SOD, CAT and POD, respectively, are positively correlated with the severities of disease significantly.