象草在南方典型母质土壤中的镉修复效应

The Remediation Effect of Napier Grass to Cd-contaminated Soil with Typical Parent Materials in Southern China

选取南方典型母质发育耕作土紫泥田和麻砂泥,通过添加不同浓度梯度的外源Cd(0,0.5,2.0,10.0,20.0mg/kg)进行盆栽试验,并结合傅里叶红外与X射线衍射等手段,研究了象草在土壤Cd胁迫下的耐受能力及修复效果。结果表明:紫泥田与麻砂泥中象草对Cd的耐性指数为0.65~0.79,均表现出较好的耐性;外源Cd浓度为0,0.5,2.0mg/kg时象草富集系数均大于1,表现出较好的Cd富集性;象草转运系数为0.60~0.84,属于非Cd超富集植物,但因地上部分生物量巨大,象草在无外源Cd添加时对土壤Cd的修复效率依然可观,且在麻砂泥中最为显著,为2.48%。另外,土壤理化性质如pH、CEC、有机官能团等不同也可导致象草对Cd的富集呈现差异。综合分析,象草更适宜于中轻度Cd污染土壤的修复,且对麻砂泥的修复效率优于紫泥田。

Pot experiment was conducted to study the tolerance and remediation effect of Napier grass to cadmium(Cd)in purple soil and granitic sandy soil using Fourier infrared and X-ray diffraction analysis methods,and the exogenous Cd was added with gradients of 0,0.5,2.0,10.0,20.0 mg/kg.The results showed that Napier grass had a good tolerance to Cd,the tolerance index was 0.65~0.79.When the concentrations of Cd were 0,0.5,2.0 mg/kg,the bioconcentration factors were more than 1,showing a good ability of enrichment to Cd.Napier grass was not hyper accumulator of Cd because of transfer factors ranged from 0.60 to 0.84,but its restoration efficiency on Cd-contaminated soil was considerable when no exogenous Cd was added resulted from its enormous above ground biomass.And it was the most significant in granitic sandy soil,i.e.,2.48%.In addition,the differences in soil physicochemical properties such as pH,CEC and organic functional groups could also lead to the differences in Cd enrichment in Napier grass.Comprehensive analysis showed that Napier grass was more suitable for the remediation of moderately Cd-contaminated soil,and the remediation efficiency of granitic sandy soil was better than that of purple soil.