Relationships between changes of active oxygen scavenging system of wheat under drought and chilling cross-stress and cross-adaptation

Relationships between changes of the active oxygen scavenging system of wheat seedlings under drought and chilling cross-stress and cross-adaptation was studied with sand culture in artificial illumination incubator.The result showed that the activity of SOD,CAT and content of GSH reduced and the POD activity and AsA content increased under one stress(drought or chilling),but in general,the function of active oxygen scavenging system decreased and the relative permeability of plasma membrane increased(membrane system was injured).Under drought and chilling cross-stress(drought + chilling or chilling + drought), the activity of SOD,CAT,POD and content of GSH and AsA increased obviously, and the relative permeability of plasma membrane reduced and approached normal level(control experiment level).It showed that the 2 wheat were possessed of cross adaptation for drought and chilling,and pretreatment of one stress can increase resistance to another stress.Exogenous abscisic acid(ABA) pretreatment gave rise to increasing the function of active oxygen scavenging system in the wheat under drought and chilling stress and enhancing resistance.The results showed that there was some common physiological metabolism under different stresses,while the physiological metabolism had a direct interrelationship with ABA.