由于人口的快速增长,人类活动导致近地层O3浓度不断提高,O3浓度升高将对植物、动物和人体健康产生极大的危害.采用开顶式气室(OTC)原位实验方法,研究O3浓度升高对不同生长期冬小麦叶片抗氧化系统的影响,进而分析O3对植物的伤害机制.结果表明,O3浓度升高可导致冬小麦拔节期和抽穗期叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)和谷胱甘肽还原酶(GR)活性,以及还原型谷胱甘肽(GSH)、抗坏血酸(AsA)、丙二醛(MDA)和可溶性蛋白含量产生变化且呈现不同的变化规律.当O3浓度为120 nL·L-1时,与对照相比,冬小麦拔节期叶片SOD、CAT和APX活性分别降低50.3％、64.9％和75.5％,POD和GR活性分别提高45.1％和80.5％,MDA、AsA和GSH含量分别提高314.3％、8.4％和31.7％,可溶性蛋白含量降低47.5％.冬小麦体内抗氧化系统物质因其所处生长季节的不同以及O3浓度的不同而不同.本研究结果显示,冬小麦在O3的污染胁迫下,为了清除体内活性氧自由基的伤害,其抗氧化系统发生了极为复杂的变化,是植物自我调节的一种反应.%As human population increases rapidly, human activities cause the increase of tropospheric ozone (O3) which significantly exerts adverse effects on the health of plants, animals and human beings. In this paper, open top chambers (OTCs) under field conditions were used to investigate the antioxidant system (malondialdehyde, MDA; solu ble protein; ascorbic acid, AsA; ghitathione, GSH, superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascor-bate peroxidase, APX; ghitathione reductase, GR) of winter wheat leaf in different growing stages under elevated O3 The results indicated that the increase of O3 significantly affected the antioxidant system of winter wheat leaf both in jointing stage and heading stage. In the level of 120 nL- L-1, as compared with the control group, the activities of SOD,CAT and APX of winter wheat leaf in jointing stage decreased by 50.3%, 64.9% and 75.5%, while the POD and GR activity increased by 45.1% and 80.5%, respectively. The contents of MDA, AsA and GSH increased by 314.3%, 8.4% and 31.7%, respectively, and the content of soluble protein decreased by 47.5%. Different levels of O3 and dif ferent growing stages of winter wheat both resulted in different changes of substances in the antioxidant system. Under the stress of O3 pollution, the antioxidant system of winter wheat had an extremely complex change in order to prevent the damage caused by active oxygen species (AOS), which is the self-regulation of plants.
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