水分胁迫对植物线粒体结构和脯氨酸氧化酶活性的影响

水分胁迫期间,小麦幼苗芽鞘和棉花幼苗胚轴细胞内游离脯氨酸浓度增加;但复水后又恢复正常。电镜观察发现线粒体肿大,嵴消失。胞质中出现脂肪滴。气相层析技术分析,发现水分胁迫使线粒体脂肪酸组成及含量有明显变化;不饱和脂肪酸含量增加。随着水分胁迫时间的延长,脯氨酸氧化酶活性也明显下降。设想水分胁迫使线粒体结构和组分发生了不利于脯氨酸氧化酶活性表达的变化,因而抑制了酶活性。

EFFECTS OF WATER STRESS ON THE MITOCHONDRIAL STRUCTURE AND THE ACTIVITY OF PROLINE OXIDASE IN PLANTS

The content of free proline in cytoplasm, the activity of proline oxidase, fatty acids and fine structure of mitochondria were investigated with the etiolated seedlings of cotton (Gossypium hirsutum Daizi No. 15) and wheat (Triticum sativum Yang Mai No. 1)grown in darkness in 0.3 mol L~(-1) mannitol medium. The free proline content increased enormously both in coleoptiles of wheat and in hypocotyls of cotton during water stress, but returned to that in normal levels after recovery of water. During water stress the percentage of unsaturated fatty acids increased and the contents of fatty acids changed in mitochondria, and the activity of proline oxidase in the inner mitochondrial membranes declined correspondingly. It seems that changes in membrane lipid composition and membrane structure during water stress bring about changes of the activity of the proline oxidase in the membrane.