弯囊苔草对Pb-Cd-Zn复合污染的耐受性及富集能力

摘要

通过水培实验,研究了三种浓度的Pb-Cd-Zn复合污染下弯囊苔草对重金属的耐受性及富集能力.结果显示,弯囊苔草在设计的中低浓度下能正常生长,随着Pb、Cd、Zn浓度增加,叶片中POD和CAD活性以及MDA和Pro含量随着金属离子浓度增加表现出显著升高的趋势,叶绿素含量表现出明显降低趋势,SOD的活性表现出先升高后降低的趋势.弯囊苔草中积累的Pb、Cd、Zn含量随着浓度的增加而增加,地下部分重金属离子含量显著高于地上部分,表明根系对Pb、Cd、Zn均有较强的滞留效应,平均滞留率均大于50％,中低浓度下弯囊苔草对Pb、Cd、Zn的转移系数均小于1.弯囊苔草在设计的高浓度胁迫下无法生长.研究表明弯囊苔草对Pb-Cd-Zn复合污染水体有较强的耐性,可以作为低、中浓度Pb-Cd-Zn复合污水的修复植物材料.%Tolerance and bioaccumulation of lead (Pb),cadmium and (Cd) zinc (Zn) by Carex dispalata grown in the presence of different concentrations of these heavy metals were investigated using water culture method.The results indicated that Carex dispalata could not survive in the nutrient culture containing the highest levels of heavy metals.Furthermore,the activities of peroxidase (POD) and catalase (CAT) and contents of Malondialdehyde (MDA) and proline (Pro) in Carex dispalata increased significantly with the increasing concentrations of heavy metals in nutrient cultures.While the content of chlorophy Ⅱ showed decreasing trend with the increasing concentrations of heavy metals in nutrient cultures,and the activity of superoxide dismutase (SOD) in Carex dispalata increased firstly and then decreased.Concentrations of Pb,Cd and Zn in Carex dispalata increased with increasing levels of metals in nutrient cultures.The levels of these metals in roots of Carex dispalata were higher than those in shoots.The root of Carex dispalata presented a substantial retention function for heavy metals,and the average retention rates of roots was greater than 50 ％.The biological transfer coefficient of Pb,Cd and Zn in Carex dispalata was less than one.The present study indicated that Carex dispalata could be suitable for phytopurification and phytoremediation of wastewater with low-medium concentrations of Pb,Cd and Zn.