MTBE和Cd复合作用对土壤酶活性和小麦吸收重金属的影响

Combined Effects of MTBE and Cd on Soil Enzyme Activity and Heavy Metal Uptake of Wheat

采用盆栽试验研究不同浓度(0,5,10,50,100,200,300,400,500mg/kg)的MTBE和相同浓度系列MTBE与Cd(5mg/kg)复合作用对土壤酶活性的影响以及复合作用对小麦吸收重金属的影响。结果表明:MTBE作用下土壤脲酶、蔗糖酶、过氧化氢酶活性表现出先增高后降低的趋势,在MTBE浓度为50mg/kg时,3种土壤酶活性达到最高值,与对照相比分别提高了14.7%,4.2%,10.1%;复合作用下3种土壤酶活性表现出先降低然后升高再降低的趋势,在MTBE浓度为10mg/kg时与对照相比分别降低了17.2%,8.7%,14.0%;在MTBE浓度为50mg/kg时,可以缓解重金属对3种土壤酶活性的抑制作用,但酶活性仍低于空白组;在MTBE浓度为200,300,400,500mg/kg时,2种物质的复合作用抑制了3种酶的活性;复合作用对土壤酶活性的抑制比MTBE作用要明显;复合作用下小麦中重金属含量表现出增高的趋势,这说明MTBE增加了Cd的可迁移性,从而使土壤中的Cd含量降低。

The pot experiment was conducted to investigate combined effects of MTBE and Cd on soil enzyme activity and heavy metal uptake of wheat under different concentration of MTBE（0,5,10,50,100,200,300,400,500 mg/kg） and Cd（5 mg/kg） single and combined function.The results showed that soil enzyme activities（such as urease,invertase,catalase） initially increased and then decreased under the function of MTBE.Three kinds of soil enzyme activities reached the highest at the concentration of 50 mg/kg,and increased by 14.7%,4.2%,10.1% compared with CK.While the soil enzyme activities initially decreased first,then increased,and decreased again under the combined function.Soil enzyme activities decreased by 17.2%,8.7%,14.0% compared with CK at the MTBE concentration of 10 mg/kg.MTBE could relieve the soil enzyme activities which caused by the heavy metal at the concentration of 50 mg/kg,but the soil enzyme activities were still lower than those of CK.The combined function restrained the soil enzyme activities（such as urease,invertase,catalase） at the concentration of 200,300,400,500 mg/kg of MTBE.The combined function of the inhibition of the soil enzyme activities were more significant than single pollution.The heavy metal uptake of wheat leaves increased under the combined function.The results indicated MTBE enhanced the transportable Cd,and it decreased Cd content in the soil.