无性系金丝柳在北方典型镉污染土壤修复中的应用

Application of Salix×aureo-pendula in the Remediation of Typical Cadmium Contaminated Soil in North China

为探究植物修复技术在镉(Cd)污染土壤中的应用特征及修复效果,以不同Cd污染程度的实际土壤为对象,通过扦插栽培的方式,对比金丝柳在不同Cd污染土壤中对Cd的耐受、富集、转移能力及修复效率。结果表明,随Cd污染浓度增加,无性系金丝柳地上和地下部生物富集系数(BCF)都增加,且地上部富集能力高于地下部,是地下部的3.56~7.28倍。当生长条件相同时,2年生金丝柳BCF和Cd含量都显著高于1年生,是1年生的1.66倍和1.47倍。由此可见,无性系金丝柳对Cd具有较高的耐受性和累积能力,且生长时间越长,从土壤中吸收的Cd相对越多。而在2种Cd污染土壤中,无性系金丝柳都倾向于将部分Cd转运到地上部来缓解Cd的毒性,且地上各部位相较于根部具有更大的Cd容量。在重度污染土壤中金丝柳枝、叶、茎和根部Cd去除量分别是中度污染土壤中的1.01、1.34、1.93、3.47倍,因此在重度Cd污染土壤中无性系金丝柳能去除更高量的Cd,具有较高的Cd提取量和累积能力。综上所述,无性系金丝柳具有较高的耐受性和累积能力,在较高Cd污染土壤中能去除更高量的Cd,具有修复中重度Cd污染土壤的能力。

The experiment is to explore the application characteristics and repair effects of phytoremediation technology in cadmium(Cd) contaminated soil. Taking the actual soil with different levels of Cd pollution as the target,the Salix×aureo-pendula was selected by cutting cultivation to compare the tolerance,enrichment,transfer ability and remediation efficiency of Salix×aureo-pendula in different Cd polluted soil. The results showed that with the increase of Cd pollution concentration,the bioconcentration coefficient(BCF) of the aboveground and underground parts of Salix × aureo-pendula increased,and the above-ground enrichment ability was higher than that of the underground,which was 3.56-7.28 times of that of the underground. When the growth conditions were the same,the BCF and Cd contents of the 2-year-old Salix×aureo-pendula were significantly higher than that of the 1-year-old,which was 1.66 times and 1.47 times of that of the 1-year-old.It can be seen that the cloned Salix×aureo-pendula has higher tolerance and accumulation ability to Cd,and the longer the growth time,the more Cd is absorbed from the soil. In both the Cd-contaminated soils,the clonal Salix × aureo-pendula tends to transport part of Cd to the shoots to alleviate the toxicity of Cd,and the aboveground parts have a larger Cd ’ capacity’ than the roots. The removal of Cd from the branches,leaves,stems and roots of the heavily polluted soil is 1.01,1.34,1.93 and 3.47 times of that of the moderately contaminated soil,respectively. Therefore,in the heavily Cd-contaminated soil,the clonal Salix × aureopendula can remove a higher amount of Cd,and has higher Cd extraction and accumulation ability. In summary,the clonal Salix×aureo-pendula has higher tolerance and accumulation ability,can remove higher amount of Cd in higher Cd contaminated soil,and has the ability to be applied to medium and heavy Cd contaminated soil.