水分胁迫对玉米苗期膜损伤及有关酶活性的影响

Effects of Water Stress on Membrane Damage and Changes of Some Related Enzyme Activitics in Leaf of Maize Seedling

水分胁迫下，３个测试的玉米杂交种（玉单３５８，南校８号，桂三２号）幼苗叶片束缚水含量（ＢＷＣ）有所提高，以玉单３５８的ＢＷＣ升幅最高。自由水含量（ＦＷＣ），总含水量ｔＴＷＣ）和叶片相对含水量（ＲＷＣ）均有所下降．下降水平为南校８号＞桂三２号＞玉单３５８。叶片可溶性糖和游离脯氨酸含量增长水平为玉单３５８＞桂三２号＞南校８号．膜脂过氧化产物丙二醛（ＭＤＡ）增加幅度和质膜相对透性大小为南校８号＞桂三２号＞玉单３５８．超氧物歧化酶（ＳＯＤ）、过氧化物酶（ＰＯＤ）和过氧化氢酶（ＣＡＴ）等保护酶活性则为：玉单３５８＞桂三２号＞南校８号。上述结果表明，花粉植株杂交种玉单３５８的抗水分胁迫能力比桂三２号和南校８号强．

Some physiological characters of three maize cultivars (Zea mays L. cv., Yu Dan 358,Gut Shan No. 2 and Nan Xiao No. 8)which treated with natural or inductive drought stress by polythylene glycol were studied comparatively. The main results were as followed: The relative water content, content of free water and content of total water in leaves of three maize cultivars were decreased significantly during be hit by drought stress. The trend of declining was by Nan Xiao No. 8>Gut Shan No. 2>Yu Dan 358. On the contrary, content of bou.nd water was increased slightly, the increasing degree of Nan Xiao No. 8 was the lowest. Value of all these water indexes in Yu Dan 358 were the highest) that of Nan Xiao No. 8's were the lowest. Water potential in leaves of three maize cultivars was decreased markedly during be hit by drought stress. The degree of declining was by Nan Xiao No. SMGui Shan NO. 2>Yu Dan 358. Contents of soluble sugar and free proline in leaves of three maize cultivars were increased considerably during be hit by drought stress. The trend of increasing was by Yu Dan 358>Gui Shan No. 2>Nan Xiao No. 8. The plasmalemma permeability of leaf cell markedly increased during be hit by drought stress. Content of malondiadehyde, as a product of membrane lipid peroxidation, increased too. These results showed that the membrane system of cell was damaged. Degree of damaged was by Nan Xiao No. 8>Gui Shan No. 2>Yu Dan 358. The activity of superoxide dismutase increased at first, and then declined. The activity of catalase declined in various degrees. The change of peroxidase activity was not apparent. 'I'he total enzymatic activities of clear away harmful radicals in Yu Dan 358 were the highest. That of Nan Xiao No. 8's were the lowest. Above Inentioned results showed that the drought resistance of Yu Dan 358 is the most powerful than that of the other two cultlvars.