3种地被竹对重金属复合污染农田土壤的修复潜力

Remediation Potential of Three Dwarf Bamboos on Farmland Soils Contaminated with Mixed Heavy Metals

选用菲黄竹、箬竹和鹅毛竹这3种地被竹在Cu、Zn、Cd和Pb复合污染农田上进行为期2 a的田间试验,分析其在污染条件下的生长富集特征,并结合土壤中重金属含量变化情况,对比3种地被竹对重金属复合污染的修复潜力.结果表明,菲黄竹在重金属复合污染农田上适应性最好,生长株数为种植时的63.8倍.3种地被竹体内重金属含量均集中在根部,且对Cd的富集效果最好,对Pb的富集能力最差.3个竹种的根部和鞭部的Cd富集系数均远大于1,其中菲黄竹和箬竹根部富集系数分别为17.68和14.63.重金属累积量则主要集中在根部和鞭部,其中菲黄竹对Cu、Zn和Cd的累积量分别为157.14、363.3和7.18 g·hm^(-2),高于鹅毛竹和箬竹.种植2 a后,地被竹周围表层土壤中重金属含量较种植前均有下降,其中Cd含量下降最多,为39.6%~40.4%.此外,菲黄竹和鹅毛竹根际土壤中Cu、Zn和Cd含量均显著小于表层土壤(P<0.05).试验证明,3种地被竹对Cd均有较强富集能力,可作为Cd修复植物继续深入研究;菲黄竹在生长状况、重金属富集量和累积量等方面均优于箬竹和鹅毛竹,对土壤重金属复合污染修复潜力最高.

A two-year field experiment was carried out in a Cu-Zn-Cd-Pb-contaminated field with Sasa auricoma,Indocalamus tessellatus,and Shibataea chinensis Nakai to investigate their growth and accumulation characteristics.Based on changes in heavy metal content in the soil,we compared their phytoremediation potentials for the combined pollution of heavy metals.After two years of planting,S.auricoma showed the best tolerance to soil contaminated by heavy metals,with the number of plants being 63.8 times that at the time of planting.For each bamboo type,heavy metals were most concentrated in the root,with the best enrichment ability of Cd and worst ability of Pb.The bioconcentration factor of Cd in the roots was far greater than 1 for all three species,with 17.68 for S.auricoma and 14.63 for I.tessellatus.The accumulation of heavy metals was mainly concentrated in the roots and rhizomes,and the accumulations of Cu,Zn,and Cd in S.auricoma were 157.14,363.3,and 7.18 g·hm^(-2),respectively,which were higher than those of I.tessellatus and S.chinensis Nakai.Compared with that before planting,the content of heavy metals in the non-rhizosphere soil decreased after two years of planting,among which Cd content decreased the most,from 39.6%-40.4%.In addition,the contents of Cu,Zn,and Cd in rhizosphere soil of S.auricoma and S.chinensis Nakai were significantly lower than those in non-rhizosphere soil(P<0.05).The results showed that the three species had strong accumulation ability of Cd and could be further studied as Cd-repaired plants.The growth condition and content and accumulation of heavy metals in S.auricoma were excellent among the dwarf bamboos,which showed the highest phytoremediation potential.