关键词: 沙生植物, 保护酶, 自然脱水, 高温胁迫, 科尔沁沙地

Abstract: The protective enzymatic system of several desert plants grown in different kinds of dunes and exposed to air dehydration, drought stress, high temperature was studied in this paper to understand further the relationship between the activities of protective enzyme and lipid peroxidation in the plants, and to test resistance of plant to adverse environment. The results showed that the increase of activities of superoxide dismutase (SOD) and peroxidase (POD) were positive related to the increase of malondialdehyde (MDA) under stresses. Agriophyllum squarrosum, Convolvulus chinensis grown in shifting sand dune were dead even though activity levels of SOD, POD increased much greater under stresses, maybe due to the rate of scavenging by SOD, POD is lower than that of accumulation in free radical. Artemisia halodendron grown on semi fixed sand dune was alive, but activities of SOD, POD increased very little, and kept lower level of SOD, POD under stress and nontreatment, so the resistance to bad condition may depend on many ways and physiological mechanisms. Pennisetum centrasiaticum and Setaria viridis grown on fixed sand dune were alive, their characters with increasing activities of SOD, POD under stresses and kept them higher level before treatment implied that they were true kinds of plants relying on the protection of SOD, POD against lipid peroxides to increase the ability to acclimate to adverse conditions.

Key words: Desert plant, Protective enzyme, Atmosphere dehydration, High temperature stress, Horqin Sandland