Study on the activities of antioxidative enzymatic system of the common plant populations in desertification process on the southeast edge of Mu Us Sandy Land | 毛乌素沙地东南缘沙漠化共有种植物叶片抗氧化酶活性研究

صينى. 分析沙漠化过程中，不同沙漠化阶段共有种植物叶片抗氧化酶活性的变化特征，旨在为沙漠化防治中植被的选择提供理论基础。在毛乌素沙地东南缘，采用植被动态学中群落的空间序列方法，以植被盖度为依据，将沙漠化过程划分为5个阶段（非沙漠化、潜在沙漠化、轻度沙漠化、中度沙漠化、重度沙漠化），在每个阶段选取3个1 m×1 m的样方，采集沙漠化共有种植物本氏针茅（Stipa bungeana）、糙隐子草（Cleistogenes squarrosa）、达乌里胡枝子（Lespedeza davurica）、油蒿（Artemisia ordosica）、牛心朴子（Cynanchum komarovii_）的叶片，分析不同沙漠化阶段共有种植物叶片中超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、过氧化物酶（POD）活性的变化。沙漠化过程中，共有种植物叶片中3种抗氧化酶活性变化各异，表现出不同的沙漠化适应性。其中，本氏针茅和糙隐子草SOD、CAT和POD活性变化幅度较大，均呈现出先增加后降低的趋势；达乌里胡枝子SOD和POD活性均呈现出先升高后降低再升高的变化趋势，且POD活性变化幅度较SOD小，CAT活性变化趋势不明显；油蒿和牛心朴子SOD、CAT、POD活性均呈波动性上升趋势，表明这3种酶在协同抑制膜脂过氧化作用、维持膜系统稳定性方面起着重要的作用。本氏针茅和糙隐子草叶片抗氧化酶对沙漠化过程反应敏感，这2种植物抗逆性较弱；SOD在达乌里胡枝子抗性机理形成方面发挥着主要作用；油蒿和牛心朴子叶片中的3种抗氧化酶在保护植物膜系统方面能协同作用，故这2种植物沙漠化抗性较强。

إنجليزي. The study analyzed the adapting mechanism of the common plant populations in different stages in desertification process, aiming to provide theoretical basis for selecting suitable plant populations. Taking the distinct desertification region on the southeastern edge of Mu Us Sand Land in Yulin area as the study area, by methodology of “Temporal for Spatial”, the desertification was divided into five stages(Non-desertification stage, Potential desertification Stage, Mild desertification stage, Moderate desertification stage, Severe desertification stage), in each stage three 1 m×1 m quadrats were randomly selected, the leaves of the common plant populations, Stipa bungeana, Cleistogenes squarrosa, Lespedeza davurica, Artemisia ordosica, Cynanchum komarovii were collected, the activities of SOD, CAT and POD of different plants in lab were measured. In desertification process, the activities of antioxidative enzymatic system of the five plants changed differently, these five plants proved different adapting mechanisms. SOD, CAT and POD activities of Stipa bungeana and Cleistogenes squarrosa changed largely, increased first and then decreased; SOD activity of Lespedeza davurica increased firstly and then decreased and again rose, POD activity had small change, CAT activity was relatively stable; SOD, CAT and POD activities of Artemisia ordosica and Cynanchum komarovii rose with fluctuation, which showed that the three antioxidative enzymes could restrain the membrane lipid peroxidation and maintain the stability of the membrane system cooperatively. Stipa bungeana and Cleistogenes squarrosa reacted sensitively in desertification process, the stress resistance was weak; SOD of Lespedeza davurica was the main enzyme for the stress resistance of it; Artemisia ordosica and Cynanchum komarovii could adapt to the desertification by the combination of SOD, CAT and POD, and had a good adaptability to desertification.