水分胁迫及复水过程中小麦抗氧化酶的变化

对两个抗旱性不同的小麦品种进行水分胁迫和复水处理，研究其抗氧化酶活性的响应。在水分胁迫下，陇春-20的相对含水量高于优鉴-24，复水24h后，优鉴-24的相对含水量恢复较快且高于陇春-20。水分胁迫下，优鉴-24中H2O2含量增加迅速，而且各阶段含量均高于陇春-20，复水后两个品种的H2O2含量都下降，这表明优鉴-24在水分胁迫时受到更严重的氧化胁迫。采用温和胶电泳结合抑制剂实验发现小麦有3条Mn—SOD，一条Fe—SOD和Cu／Zn-SOD同工酶带，CAT同工酶有3条谱带。在水分胁迫和复水期间，优鉴-24的SOD和CAT活性高于陇春-20，随着水分胁迫程度的增加，两个品种的SOD和CAT活性都增强，复水后，优鉴-24的SOD活性继续增强，而陇春-20的Mn—SOD—3活性略微降低，Fe—SOD和Cu／Zn—SOD活性略微升高，陇春-20的CAT活性降低。水分胁迫诱导了Mn—SOD—1在优鉴-24及Mn—SOD-2和Fe—SOD在陇春-20中的表达。

Changes of antioxidant enzymes in wheat subjected to water deficit and rewatering

Changes of antioxidant enzymes were investigated in two wheat (Triticum aestivum cv.) cultivars with different sensitivities to drought under water deficit and rewatering. LC-20 showed a higher relative water content than YJ-24 during the whole stress period. In order to analyze the changes of superoxide dismutases (SODs) and catalase (CAT), native PAGE analysis of protein extract was performed. Wheat leaves had three isoforms of Mn-SOD, one isoform of Fe-SOD and Cu/Zn-SOD. Three CAT isoforms were identified in the protein extract from wheat leaves. SOD and CAT isoforms were enhanced both in two cultivars under water stress. The intensities of CAT isoforms increased continuously in YJ-24 after rewatering and slightly decreased in LC-20. Except for Mn-SOD-3 isoform in LC-20, other isoforms of SOD continuously increased in two cultivars. The results suggest that water stress activates SOD and CAT isoforms in the drought-induced oxidative stress events in the wheat.