螯合剂对小麦幼苗吸收金属以及土壤金属形态的效应  

Metal uptake of wheat seedlings and metal distribution after the addition of EDTA,[S,S]-EDDS and DTPA

作　　者：丁竹红[1] 胡忻[2] 张宇峰[1] 

机构地区：[1]南京工业大学环境学院,江苏南京210009 [2]南京大学现代分析中心,江苏南京210093

出　　处：《生态环境学报》2010年第1期97-101,共5页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(20607010)

摘　　要：本文通过盆栽试验研究三种螯合剂(EDTA、[S,S]-EDDS、DTPA)对小麦幼苗吸收土壤中重金属及其它微量元素的效应,并且通过改进的BCR连续提取法分析了种植后土壤样品中金属元素的形态。结果表明:EDTA、DTPA的添加导致小麦幼苗地上部分生物量以及叶片叶绿素a含量显著下降。螯合剂的存在明显增加了Pb和Mn在幼苗根部和茎叶的富集,并增加其由根部向茎叶的传输,但对Fe和Ni的作用比较小。小麦幼苗收获时,除Zn之外,其它元素酸溶/可交换态金属含量与对照组相比均有非常显著的增加,而各元素的可还原态由于EDTA等螯合剂的添加而有明显下降。添加螯合剂的情况下,富集量与酸溶/可交换态含量之间的相关系数大大提高,且各处理组茎叶富集量与酸溶/可交换态之间呈显著(P<0.05)或极显著相关(P<0.01)。因此,三种螯合剂的添加主要影响的是生物可利用形态以及潜在的生物可利用形态,并且可能导致可还原态以及可氧化态向酸溶/可交换态转变,增加金属的生物可利用性,从而也增加潜在生态风险。Pot experiments were carried out to investigate the metal （Cu, Pb, Zn, Ni, Fe, and Mn） uptake oftbe wheat seedlings at the presence of EDTA, [S,S]-EDDS and DTPA. Modified BCR sequential extraction procedure was employed to test the distribution of the metals in the soil atfer the wheat seedlings was harvested. Biomass and chla of wheat seedlings decreased significantly （P〈0.05） because of the addition of EDTA, and DTPA. The concentration of Pb and Mn in roots and shoots of the seedlings and their transfer from root to shoot were all greatly improved due to the addition of the chelating agents, however, Fe and Ni accumulation was af- fected slightly. The exchangeable/acid soluble fraction of Cu, Pb, Ni, Fe, and Mn greatly increased at the end of the experiment for chelating agents treatments. The reducible fraction of all the tested metals reduced due to the addition of chelating agents. The coeffi- cient （r2） of linear correlation between metal concentration in wheat seedlings and exchangeable/acid soluble fraction extracted using BCR sequential extraction increased with the use of chelating agents. Therefore potential bioavailable fractions were the main frac- tions that affected by the chelating agents, and reducible fraction and oxidizable fraction may transform to more mobile fraction. In view of the increased mobility of the tested metals contributed to the larger proportion of exchangeable/acid soluble fraction in the soil with the use of chelating agents, measurements should be taken to avoid the potential risk caused by the possible their transfer.

关 键 词：重金属 形态 螯合剂 植物修复 

分 类 号：X131.3[环境科学与工程—环境科学]