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重金属镉及盐胁迫对白榆幼苗生理特性的影响

Effects of Heavy Metal Cd and Salt Stress on Physiological Characteristics of Ulmus pumila Seedlings

  • 摘要: 研究白榆对单一及复合土壤污染的抗性旨在为复合污染地生态恢复提供理论依据,该文以1年生白榆苗为试验材料,采用土培试验研究不同质量浓度镉(Cd)、盐(NaCl)单一及复合胁迫对其叶绿素、丙二醛(MDA)、过氧化物酶(POD)及超氧化物歧化酶(SOD)等生理生化指标的影响。研究结果表明,Cd、NaCl复合胁迫对白榆的叶绿素、MDA、POD、SOD指标比Cd、NaCl单一胁迫的影响作用更明显;在胁迫过程中,白榆叶绿素含量随着单一及复合胁迫梯度的增加而上升;MDA含量随着单一及复合胁迫梯度增加而降低;POD活性和SOD活性随着单一及复合胁迫表现为低质量浓度上升高质量浓度降低。在Cd胁迫水平大于200 mg/L、NaCl胁迫水平在大于500 mmol/L时,白榆的POD、SOD活性会不同程度地受到抑制且复合胁迫比单一胁迫对桑树的破坏作用更明显。

     

    Abstract: To provide theoretical basis for the study of Ulmus pumila resistance to single and compound soil pollution and ecological restoration of compound contaminated areas. the effects of different concentrations of Cd stress and salt stress on chlorophyll, malondialdehyde(MDA), peroxidase(POD) and superoxide dismutase(SOD) of Ulmus pumila seedlings were studied by soil culture experiment. The results showed that the effects of Cd and NaCl combined stress on chlorophyll, MDA, POD and SOD of Ulmus pumila were more obvious than that of Cd and NaCl single stress. In the process of stress, chlorophyll content of Ulmus pumila increased with the increase of single and compound stress gradient. The MDA content of Ulmus pumila decreased with the increase of single and compound stress gradients. POD activity and SOD activity increased with low concentration and decreased with high concentration under single and combined stress. The results showed that POD and SOD activities of Ulmus pumila were inhibited in different degrees when Cd stress level was higher than 200 mg/L and NaCl stress level was higher than 500 mmol/L, and the damage effect of composite stress on Ulmus pumila was more obvious than that of single stress.

     

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