铜、锌对3种常见乔木抗氧化指标的复合影响

为了解不同浓度铜（Cu）、锌（Zn）重金属污染土壤对乔木抗氧化指标的影响以及为植物修复蠡河重金属污染岸带提供理论依据，选取广玉兰（Magnoliagrandiflora）、香樟（Cinnamomumcamphora）、榉树（Zelkovaschneideriana）幼苗，采用土培法浇灌重金属溶液模拟土壤污染环境，研究不同浓度重金属Cu／Zn对乔木脯氨酸含量、过氧化物酶活性、过氧化氢酶活性及丙二醛含量的单一及复合影响。实验表明，单一Cu胁迫对广玉兰、香樟和榉树的毒害作用较单一，Zn胁迫严重；Cu／Zn复合作用下，3种乔木抗氧化指标均在Cu15和Zn110时达到最大值，表现出较强的抗性，而后随着复合作用强度增加，重金属对其毒害作用增大；75μg／gCu和210μg／gZn单一及复合胁迫时，广玉兰丙二醛含量相对香樟和榉树较接近对照值，过氧化物酶和过氧化氢酶活性较大，脯氨酸含量差别不大。综合分析，不同乔木在不同浓度重金属胁迫下抗氧化指标作出不同响应，广玉兰对高浓度Cu／Zn胁迫不敏感，承受能力和抗性较强，适合于修复Cu／Zn污染较严重土壤。

Combined Effects of Copper and Zinc on Anti-oxidation Indices of Three Kinds of Trees

In order to understand the effects of different concentrations of combined pollution of both copper （Cu） and zinc （Zn） on anti-oxidative indices of trees and provide a theoretical basis for the phytoremedy of the polluted regions in the Li River, the single and combined effects of different concentrations of Cu and Zn on the activities of catalase and peroxidase as well as the contents of malondialdehyde and proline in Magnolia grandiflora, Cinnamomum camphora and Zelkova schneideriana were investigated in a simulated test where the pollution of heavy metals in soil was simulated by cultivation. The results indicated that the single Cu stress exhibited more harmful effects on Magnolia grandiflora, Cinnamomum camphora and Zelkova schneideriana than single Zn stress did. For the combined treatment of both Cu and Zn, the anti-oxidative indices of three kinds of trees reached the maximum at Cul5 and Zn110, and showed strong resistance. As the compound concentrations of both Cu and Zn increased, the toxic effects of heavy metal increased. Under the single and combined treatments of 75μg/g Cu and 210μg/g Zn, the content of malondialdehyde in Magnoliagrandiflora approached to the level of the control. The activities of catalase and peroxidase in Magnolia grandiflora were greater than those of Cinnamomum camphora and Zelkova schneideriana, and the content of proline had no significant difference among the three trees. Together, the anti-oxidative indices in different trees had different responses to heavy metals at different concentrations. As Magnolia grandiflora was not sensitive to the stress of both Cu and Zn at high concentrations, and had strong tolerance and resistance, it was a better candidate to remedy soil polluted by copper and zinc.