干旱诱导作物叶片膜损伤和膜脂过氧化的关系

聚乙二醇根际胁迫和自然干旱胁迫都使小麦、玉米和大豆幼苗叶片的膜透性增加、膜旨过氧化程度下降。ＰＥＧ胁迫下抗氧化酶活性发生变化，中度胁迫时，小麦的超氧化物歧化酶和过氧化物酶（ＰＯＤ）活性上升，而过氧化氢酶活性下降；玉米ＳＯＤ活性没有变化。

Relationship between Membrane Damage and Lipid Peroxidation in Crop Leaves Induced by Drought

The polyethylene glycol (PEG) osmotic stress (-0 2,-0 3 and -4 0 MPa) and natural drought (1,2 or 3 days) increased the membrane permeability, while the content of thiobarbituric acid reactive substances (TBARS) decreased in wheat, maize and broadbean. The changes in antioxidative enzymatic activities under PEG osmotic stress were as follows: Under a moderate stress (relative water content decreased for 10 20%), superoxide dismutase (SOD) and peroxidase (POD) increased, and catalase (CAT) decreased in wheat; SOD did not change, POD increased significantly and CAT decreased significantly in maize; POD did not change but SOD and CAT decreased in broadbean. Under a severe stress (relative water content decreased more than 20%), the activities of all three enzymes in all three crops decreased significantly. Both moderate and severe stresses caused an increase in lipid soluble antioxdative activities.