艾比湖地区典型乔灌群落水盐胁迫下土壤重金属对酶活性的影响

Effects of Heavy Metals on Soil Enzyme Activities in Typical Arbor-shrub Communities under the Different Water and Salt Conditions in Ebinur Lake Area

为探讨自然水盐胁迫下土壤重金属对酶活性的影响,对艾比湖国家级自然保护区内3种典型植被群落水盐胁迫下土壤Cd,Cr,Cu等5种重金属和过氧化氢酶、磷酸酶、脲酶等4种酶活性进行了研究。结果表明:不同群落类型土壤水盐、酶活性和重金属含量方面具有各自特征,典型群落中土壤重金属含量对过氧化氢酶活性的影响更为强烈,而这种现象在耐旱植物梭梭中尤为明显,土壤水分受限情况下,以Cd,Cr和Zn为代表的土壤重金属对土壤酶活性有一定影响。在水盐环境较好、重金属含量较少的自然土壤中,土壤重金属对酶活性具有较高的促进作用;重金属含量较少,盐胁迫对酶活性抑制作用明显;水分胁迫对酶活性限制较小,土壤重金属对酶活性的影响小于土壤可溶性总盐,说明自然条件下土壤盐胁迫对土壤酶活性具有强烈的抑制作用;研究区Cd和Cr对土壤酶表现出激活作用,Cu对土壤酶活性的影响不明显,Mn和Zn对土壤酶则多表现出抑制效应。

In order to explore the effects of heavy metals on soil enzyme activities under the stress of water and salt,5 kinds of heavy metals（Cd,Cr,Cu,Mn and Zn） and four kinds of enzymes（Catalase,Phosphatase,Urease and Sucrase） were examined in three kinds of typical arbor-shrub communities（Populus euphratica,Tamarix ramosissima and Haloxylon ammodendron） under the different habitats in Ebinur Lake Area.The results indicated that different communities had their own characteristics in terms of soil moisture,salt,enzyme activities and heavy metals contents.Heavy metal contents exerted more intense influence on Catalase,particularly in Haloxylon ammodendron which belonged to drought-tolerant plant,Cd,Cr and Zn had a certain influence on enzyme activities under limited soil moisture situations.There were better water and salt environment,and less heavy metal contents in natural soil in which soil enzyme activities were well prompted by heavy metal.Soil enzyme activities were restrained significantly by salt press when the heavy metal contents were less.Water stress imposed little restrictions on enzyme activities,and soil heavy metal contents had less influence on enzyme activities than that of the soil total soluble salt,demonstrating that soil salt stress decreased enzyme activities intensively under natural conditions.Cd and Cr played active function in soil enzyme activities,and Cu had no obvious effect on soil enzyme activities,however,Mn and Zn played inhibitory function in soil enzyme activities.