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，研究了水稻结实期丙二醛（MDA）含量、光合速率、气孔导度、渗透调节物质及保护性酶活性等生理性状变化。结果表明，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剧，抗旱性弱的品种膜脂过氧化更为严重；剑叶光合速率、气孔导度和叶绿素含量迅速下降，抗旱性弱的品种比抗旱性强的品种降速快、幅度大。抽穗后0～14 d随胁迫时间的延长叶片内可溶性糖、氨基酸含量增加，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，抗旱性强的品种增加或升高的幅度大。抽穗14 d后叶片内可溶性糖、氨基酸含量下降，SOD、CAT和POD酶活性降低。试验表明，水稻叶片MDA含量、光合作用、渗透调节物质及保护性酶活性的变化幅度与品种的抗旱性密切相关。
Along with the increasing scarcity of global water resource, water shortage is crucial for restricting agricultural development in china. Rice is one of the main staple food crops in the world, and may suffer serious water stress during its growth period. Water stress during grain filling results in decreasing grain yield, and its physiological mechanism is unclear under continuance of the water stress. So study on the relationship between water stress and drought resistance in rice have become increasingly important proposals of rice scientific researches. The experiments were carried out in growth chamber to investigate the effects of water stress on MDA，photosynthetic rate, stomatal conductance, osmotic regulators and antioxidative enzyme activities in three hybrid rice cultivars (combinations) with different drought resistant abilities under both normal and drought conditions during grain filling stage. 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 in better drought resistant cultivars. During the period of water stress, decreases of photosynthetic rate, stomatal conductance and chlorophyll content in better drought resistant cultivars were obvious less than those in weaker drought resistant ones. Contents of soluble sugar and amino acid and activities of superoxide dismutase(SOD), catalase(CAT) and peroxidase(POD) in leaves increased obviously in 0–14 d after anthesis and subsequently decreased rapidly, and the increases were more in better drought resistant cultivars than in weaker drought resistant ones in 0–14 d after anthesis. These results suggest that water stress can induce physiological and biochemical changes in rice, and the changes indicate drought resistance of rice during grain filling stage. Changes of MDA content, photosynthesis, osmotic regulators and antioxidative enzyme activities are correlated significantly to drought resistance of rice varieties.
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