5种湿地植物对土壤重金属的富集转运特征

Accumulation of Soil Heavy Metals in Five Species of Wetland Plants

选择芦苇、水葱、千屈菜、扁秆藨草、长苞香蒲5种湿地植物进行盆栽实验,比较它们对土壤中的5种重金属镉、铬、汞、铅、锌的富集特性,分析重金属在各植物体和土壤中的动态分布,以评价所测植物对土壤中重金属的综合富集能力,为利用植物修复金属污染土壤提供理论依据和技术支持。结果表明:(1)种植湿地植物对土壤重金属的富集效果显著高于无植物对照,且随着处理时间的延长,土壤中重金属镉、铬、汞、铅、锌的含量均呈下降趋势。(2)湿地植物对重金属镉、铬、汞、铅、锌的富集效果差异显著,其中水葱根部对重金属镉的富集系数最大,芦苇根部对重金属铬、汞、铅、锌的富集系数均最大,千屈菜、扁秆藨草和长苞香蒲根部对5种重金属的富集系数均较小;芦苇地上部分对金属镉的富集系数最大,千屈菜地上部分对金属铬、汞、铅的富集系数均最大,水葱地上部分对金属锌的富集系数最大。(3)5种湿地植物对重金属镉、铬、汞、铅、锌的转移系数差异显著,其中扁秆藨草对土壤中镉、铬、铅、锌的转移系数均为最大,对铬和锌的转移系数均大于1,长苞香蒲对铬的转移系数大于1,仅次于扁秆藨草。其他3种植物对5种重金属的转移系数均小于1。研究表明,5种湿地植物对重金属Cd、Cr、Hg、Pb、Zn都有富集和转移的能力,但不同植物对不同重金属的富集效果不同。

The accumulation of heavy metals in wetland plants was studied in this paper. Phragrnites austra- lis , Scirpus validus , L ythrum salicaria , Scirpus planiculrnis and Typha angustata were selected to use as test plants, comparing their accumulation of five heavy metals（Cd, Cr, Hg, Pb, Zn）. The results showed that： （1） the treatment system with wetland plants has higher accumulation to five heavy metals （Cd, Cr, Hg, Pb, Zn） than that without wetland plants. While the treating time was prolonged, the con- tents of five kind of heavy metals were decreased. （2） The five wetland plants have a significant difference for bioaccumulation to five heavy metals（Cd, Cr, Hg, Pb, Zn）. Among them, the root of S. validus has the best bioaccumulation factors to Cd; P. australis has the best bioaccumulation factor to Cr, Hg, Pband Zn in its root;for the above-ground, reed has the best bioaccumulation factor to Cd. Meanwhile, we found that L. salicaria has the highest bioaccumulation factor to Cr, Hg and Pb. And S. validus has the best factor to Zn. （3） The five wetland plants have a significant variation for translocation factors to five heavy metals（Cd, Cr, Hg, Pb, Zn）. The translocation factors of S. planiculmis for Cd, Cr, Pb and Zn are all the best, of which the translocation factors for Cr and Zn are greater than 1. The translocation fac- tor of T. angustata for Cr is also greater than 1, secondly only to S. planiculmis. The translocation fac- tors of other three species of wetland plants for five heavy metals are all low.