单一重金属污染对灯心草生长及重金属积累特性的影响

    Effects of Single Heavy Metal Pollution on Growth and Heavy Metal Accumulation of Juncus effuses

    • 摘要: 盆栽试验结果表明:在设置的低浓度范围内,Cd、Pb、Cu能够刺激灯心草的生长。而As(地上部除外)、Zn在整个浓度设置范围内对灯心草的生长都表现出抑制作用,且各重金属对灯心草地下部生物量影响不显著。各重金属对灯心草生长抑制程度为:Zn>As>Cu>Pb>Cd。以灯心草生物量减产10%为依据,将土壤中Cd、Pb、Cu3种重金属临界值分别设定为10、100、100~200 mg·kg-1。灯心草不适合在Zn污染的土壤中种植,土壤中As临界值尚需作进一步的研究来确定。除Cd外,其余4种重金属主要累积于灯心草根部。回归分析表明,Cd、Pb在灯心草地上和地下部以及As在灯心草地下部的积累量与土壤中各重金属添加量之间存在显著线性关系(P<0.05)。

       

      Abstract: Effects of single element(Cu,Cd,Pb,Zn or As) pollution on growth and heavy metal accumulation of Juncus effuses were studied with pot culture.Results show that Cd,Pb and Cu stimulated growth of Juncus effuses when in the set range of low concentration,but inhibited when in the range of high concentration.As and Zn inhibited growth of Juncus effuses regardless of concentration except for As of the ground parts.The experiment also indicated that single heavy metal pollution affected yield of the biomass aboveground more significantly than yield of the biomass underground of Juncus effuses.In terms of extent of the inhabition of growth of Juncus effuses,the five heavy metals showed a decreasing order of Zn>(As>)Cu>Pb>Cd.With the decrement by 10% in biomass of Juncus effuses as a reference point,the threshold for soil Cd,Pb and Cu was set at 10,100 and 100~200 mg·kg-1,respectively.Juncus effuses did not fit Zn-contaminated soil,and the threshold for soil As remained to be a topic that needs further study.All the heavy metals,except Cd,accumulated mainly in the roots of the plant.Regression analysis revealed that contents of Cd and Pb in the shoots and roots and As in the roots were correlated significantly with the rate of heavy metals added to the soil,showing a linear curve(P<0.05).

       

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