温度与膜脂脂肪酸对不同抗冷性玉米幼苗ATP酶的影响

我们以抗冷性不同的玉米幼苗（１—４级，抗冷性递减）为材料，研究了其线粒体ＡＴＰ酶在１１℃、２４℃的活力、温度变化时其活化能（Ｅａ）的突变温度以及线粒体膜脂脂肪酸组成。结果表明在１１℃条件下，ＡＴＰ酶活力随品种抗冷性增加而增强；酶活化能折，点温度随品种抗个性增加而降低，脂肪酸的不饱和指数随品种抗个性增加而增大。这说明膜脂不饱和度控制着ＡＴＰ酶的活力，Ｅａ的折点温度受膜流动性的影响并与品种抗冷性有关，我们认为ＡＴＰ酶Ｅａ的折点温度可作为玉米幼苗抗个性生化指标。另外通过玉米幼苗抗冷性锻炼表明：ＡＴＰ酶Ｅａ折点温度没变化，说明幼苗抗冷潜力很小。

TEMPERATURE AND FATTY ACID OF MEMBRANE LIPIDS EFFECTED ON ACTIVITY OF ATPASE IN MITOCHONDRIA OF MAIZE SEEDLING BELONGING TO FOUR CHILLING-RESISTANT LEVEL

Four varieties of maize belonging to four chilling-resistant level were used to determin activity of ATPase in 11°,24℃ and Ea Transition temperature of ATPase and fatty acids composition of mitochondrialMembrane lipids. The data showed that activity of ATPase increaced as chilling resistant of variety Increacing. The stronger chilling resistant of variety ,the lower its Ea transition temperature. Index of Unsaturation fatty acid of chilling sensitive variety was smaller than that of chilling resistant variety. These indicated that unsaturation of fatty acidcontroled the activity of ATPase .Ea transition temperature Was effected by membrane fluid and correlation with chilling resistant of variety. We suggested thatEa transition temperature of ATPase could be used as biochemical index of maize seedling chilling resistant.The seedling of four maize varieties were treated in 7-8℃ for 36 hours. The result showed that there were no obiously defference between chilled samples and non chilled ones. This indicated that potenciality of chilling-resistant in maize seedling was very small.