水分胁迫对水稻结实期活性氧产生和保护系统的影响

 【目的】探索不同抗旱品种在结实期水分胁迫条件下叶片活性氧对水稻膜脂的伤害和清除机制。【方法】选用抗旱性不同的3个杂交水稻品种，在干旱棚内分别在正常供水和水分胁迫条件下，研究水稻结实期超氧阴离子自由基（O2-?）、双氧水（H2O2）、丙二醛（MDA）、还原型谷胱甘肽（GSH）、抗坏血酸（AsA）及保护性酶活性等生理性状变化。【结果】结实期随土壤水分胁迫加剧和时间延长，细胞膜脂过氧化加重，抗旱性弱的品种膜脂过氧化更为严重；O2-? 和H2O2积累迅速，抗旱性弱的品种比抗旱性强的品种积累速度快、幅度大；GSH、AsA、叶绿素含量和叶片相对含水量下降，且表现为，抗旱性弱的品种降速快、幅度大。抽穗后0～14 d随胁迫时间的延长叶片内超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和过氧化物酶（POD）3种酶活性升高，随后下降。【结论】抗旱性强的品种具有较强的抗氧化能力；O2-??积累速率、H2O2含量、叶片MDA含量、GSH含量、AsA含量及保护性酶活性的变化幅度与品种的抗旱性密切相关。

Effects of Water Stress on Active Oxygen Generation and Protection System in Rice During Grain Filling Stage

Abstract：【Objective】Rice is one of the main staple food crops in the world, but rice may suffer serious water stress during its growth period. Water stress during grain filling results in decreasing grain yeild, but its mechanisms of Generating and scavenging active Oxygen is unclear under continuance of the water stress. 【Method】The experiments were carried out in growth chamber to investigate the effects of water stress on superoxide free radical content(O2—?), hydrogen peroxide content(H2O2)，MDA content， reduced glutathione content(GSH)，ascorbic acid content (AsA)and antioxidative enzyme activities in three hybrid rice cultivars with different drought resistant abilities under both normal and drought conditions during grain filling stage. 【Result】The results indicated that water stress aggravated the membrane lipid peroxidation in rice leaves, and it was more severe in weaker drought resistant cultivars than that in better ones. O2—? and H2O2 accumulated rapidly and were more rapidly in weaker ones than that in better drought resistant cultivars. During the period of water stress, decreases of GSH content，AsA content, chlorophyll content and relative water content in better drought resistant cultivars were obvious less than those in weaker ones. Activities of superoxide dismutase(SOD), catalase(CAT) and peroxidase(POD) in leave increased obviously in 0～14d after anthesis and subsequently decreased rapidly, and those in better drought resistant cultivars were more than those in weaker ones in 0～14d after anthesis. 【Conclusion】the results showed that changes of O2—? content, H2O2 content，MDA content，GSH content，AsA content and antioxidative enzyme activities correlated significantly to drought resistance of rice varieties, and better drought resistant cultivars possesses high antioxidation capacity.