为探索水稻苗期抗旱性形态和生理机制，筛选苗期抗旱性指标，以15个水稻品种为试验材料，在干旱棚内系统研究了水、旱条件下苗期形态和生理指标的变化。结果表明，叶龄、心叶下倒数第1叶叶面积、叶鲜重、根长4个指标的相对值与反复干旱存活率显著或极显著相关，可作为苗期抗旱性的形态指标；超氧化物歧化酶（SOD）、过氧化物酶（POD）、过氧化氢酶（CAT）活性，氨基酸（AA）、抗坏血酸（AsA）、还原性谷甘肽（GSH）、可溶性蛋白质、丙二醛（MDA）含量8个指标的相对值与反复干旱存活率显著或极显著相关，可作为苗期抗旱性的生理指标。通过主成分分析确立了SOD酶活性、GSH含量、叶鲜重和叶龄4个指标相对值为水稻苗期抗旱性的综合指标，以反复干旱存活率为因变量，4个综合指标为自变量建立的回归方程对供试品种的抗旱性进行预测效果较好。
Rice plants may suffer serious water stress during its growth period, so that change their morphological characteristics and the process of physiological metabolic activity. Screening indexes of drought resistance has been focused in the concerned researched. To explore the morphological and physiological mechanisms and screen indexes of drought resistance during seedling stage in rice, in this paper, morphological and physiological characteristics correlating with drought resistance were monitored under both normal and drought conditions during seedling stage using 15 paddy rice cultivars. The results showed that relative leaf age, relative area of first leaf under the central leaf, relative leaf fresh weight, relative root length were significantly and very significantly correlated with survival percentage under repeated drought condition and could be used as the morphological indexes to identify the drought resistance. Relative activities of superoxide dismutase(SOD), catalase(CAT), peroxidase(POD) and relative contents of amino acid(AA), ascorbic acid(AsA), reduced glutathione (GSH), soluble protein and malondialdehyde(MDA) were significantly and very significantly correlated with the survival percentage under repeated drought condition and could be used as the physiological indexes to identify the drought resistance. The integrated drought resistance indexes including the relative activity of SOD, relative GSH content, leaf fresh weight, and leaf age were established by principal components analysis. The drought resistance of 15 rice cultivars was evaluated by stepwise regression equation and was basically consistent with the results from paddy field, proving it is effective to predict the drought resistance during seedling stage in rice using the integrated identification index screened out in this study.
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