镉铅的固化对苎麻生长和重金属吸收的效应

Effect of Cd and Pb immobilization by natural soil amendments on growth and heavy metal uptake of ramie( Boehmeria nivea)

为探明镉、铅重金属污染土壤固化处理对苎麻生长和重金属吸收的影响,通过盆栽试验研究了镉、铅复合污染黄褐土中施加硅藻土、膨润土、石灰石粉和沸石粉对土壤中镉、铅各形态含量的影响以及对苎麻生物量、叶片丙二醛含量及重金属镉、铅积累特性的影响。结果表明:添加沸石粉和高浓度(9~12 g·kg^(-1))硅藻土、膨润土可以显著减少土壤中镉的酸可提取态含量;添加硅藻土、膨润土和沸石粉对降低土壤中酸可提取态铅有很好的效果,降低量可达43.1%。固化剂的施加使得苎麻各部位吸收镉、铅减少,全株镉、铅累积量分别降低9.9%~62.7%和5.8%~28.4%,且固化剂施加量达到9 g·kg^(-1),对苎麻吸收镉、铅影响增大。除石灰石粉外,其他三种固化剂均使得苎麻生长受到的不良影响降低。

Pot experiments under greenhouse condition were carried out to evaluate the growth and heavy metal uptake of ramie in heavy metal contaminated yellow-cinnamon soils amended with diatomite,bentonite,limestone,zeolite at different application rates. In our study,the biomass,leaf malondialdehyde（ MDA） content,the concentrations of Cd and Pb in different parts of ramie,and fractionations of Cd and Pb in soils were determined. The results showed that zeolite,diatomite（ 12 g·kg（-1）） and bentonite（ 9 - 12 g·kg（-1）） amendment significantly reduced acid-extractable Cd concentration in soil. Furthermore,diatomite,bentonite and zeolite at all rates reduced acid-extractable Pb concentrations by up to 43. 1%. Application of amendments decreased total Cd and Pb concentrations in different parts of ramie plants. Cd and Pb concentrations in whole plants grown in amended soils were reduced by 9. 9% - 62. 7% and 5. 8% - 28. 4%,respectively. Least Cd and Pb uptake was attained at application rate of 9 g·kg（-1）. Except for limestone,other amendments alleviated the inhibitory effects of heavy metals on plant growth.