镉在土壤-香根草系统中的迁移及转化特征  

Transfer and transformation characteristics of cadmium from soil to Vetiveria zizanioides

作　　者：马文超[1] 刘媛[1] 孙晓灿[1] 陈锦平[1] 魏虹[1] 

机构地区：[1]西南大学生命科学学院三峡库区生态环境教育部重点实验室,重庆400715

出　　处：《生态学报》2016年第11期3411-3418,共8页Acta Ecologica Sinica

基　　金：国际科技合作专项(2015DFA90900);三峡后续工作库区生态与生物多样性保护专项项目(5000002013BB5200002);重庆市林业重点科技攻关项目(渝林科研2015-6);中央财政林业科技推广示范项目(渝林科推[2014-10])

摘　　要：以无植物组处理为对照,采用盆栽试验方式探讨不同Cd浓度胁迫条件下香根草根际土壤中重金属Cd的积累、迁移及转化特征。土壤Cd处理设4个浓度梯度,分别为0、2、20、80 mg/kg土壤干重。结果表明:(1)香根草可以显著降低土壤中生物有效态Cd和总Cd含量。(2)香根草各部分Cd积累量随处理浓度的增加和处理时间的延长而增加,90 d时80 mg/kg处理组地上部分和根的Cd积累量分别高达180.42 mg/kg和241.54 mg/kg。(3)各浓度Cd处理下,富集系数随着Cd处理浓度的增加而显著降低,随处理时间的延长而升高。(4)香根草地上部分Cd含量小于根部,各处理转移系数均小于1。随着处理时间的延长,中低浓度处理组的转移系数稍有降低,高浓度处理组的转移系数则显著上升。(5)种植香根草使其根际土中残渣态的Cd转化为生物有效态Cd,提高Cd清除效率。研究结果表明,香根草能够有效地吸收土壤中的Cd,降低土壤中总Cd含量,提高土壤安全性,可作为Cd污染地区植物修复的备选物种。Soil cadmium（Cd） contamination poses serious environmental concerns.The arable land area contaminated with Cd has been increasing in recent years,and it has now reached 2 × 105km2,which accounting for 1/5 of the country’s arable land.Soil Cd contamination has already jeopardized food security in China.Cd is one of the most phytotoxic heavy metals,and it is easily taken up by plants owing to its high bioavailability.Thus it easily enters the food chain and poses considerable threat to human health.This environmental concern can be overcome by phytoremediation— a powerful environment-friendly technique that involves growing plants for the extraction of toxic metals from contaminated soil.The ideal plant species for phytoremediation would be a high biomass-producing plant that can both tolerate and accumulate the desired soil contaminants.Exploitation of heavy metal uptake into plant biomass as a method of soil decontamination is limited by plant productivity and the metal concentration achieved.Therefore,more information is needed to identify the optimum plant species for phytoremediation,particularly in Cd contaminated soils.This study aimed to bridge this gap and evaluated the usefulness of Vetiveria zizanioides as a candidate species for phytoremediation.V.zizanioides is a tall（1—2m）,fast-growing and perennial tussock grass,and eurytopic in terms of habitat choice.It develops a long（3—4m）,massive and complex root system,which can penetrate the deeper layers of the soil.This species is known to have potentialapplications for phytoremediation of Cd-contaminatedsoil.Here,we conducted a microcosm experiment to determine the transfer and transformation characteristics of Cd from soil to V.zizanioides.The experiment involved two groups,each comprising four soil Cd-contaminated treatments,with or without plants,and 5 replicates per treatment.These included control,low,medium,and high treatment groups treatments,containing Cd concentrations of 0,2,20,80 mg/kg soil dry weight,respectively.Groups cont

关 键 词：香根草 CD 迁移与转化 植物修复 

分 类 号：X173[环境科学与工程—环境科学] X53