渗透胁迫对水稻幼苗膜脂过氧化及体内保护系统的影响

两个不同抗旱性的水稻品种对PEG6000渗透胁迫(-0.5MPa,-0.8MPa)的反应具有一定差异。渗透胁迫下SOD,POD和CAT活性及Vc,Car含量与膜脂过氧化水平及膜透性呈一定负相关性,表明这些指标可作为水稻抗旱育种的参考依据。

Effects of Osmotic Stress on Membrane-Lipid Peroxidation and Endogenous Protective Systems in Ricse Seedlings

Two rice cultivars, drought resistant paddy rice cultivar Xiang No. 1 and drought sensitive upland rice cultivar 763612, were used in the experiment. The effects of osmotic stress induced by PEG (-0.5 MPa, -0.8MPa) on permeability of plasma membrane, membrane-lipid peroxidation, activities of endogenous protective enzymes, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and contents of ascorbic acid (Vc) and carotenoid (Car) were studied. The results showed that under -0.5 MPa osmotic stress, contents of Vc and Car decreased, while permeability of plasma membrane, malondialdehyde (MDA) content, and activities of SOD, POD and CAT in creased; under -0.8 MPa osmotic stress, contents of Vc and Car, and activities of SOD and CAT decreased sharply with a marked increase of permeability of plasma membrane and MDA content. Under -0.8MPa, activity of POD of Xiang No.1 increased at first, then decreased, but activity of POD of 763612 decreased steadily. The responses of the two cultivars to osmotic stress were different. Under osmotic stress, there was a negative correlation of the activities of endogenous protective enzyme systems and the contents of Vc and Car with the level of membrane-lipid peroxidation and the permeability of plasma membrane. It is suggested that these parameters may be used as important indexes for breeding drought resistant rice.