摘要
通过模拟基于干旱区绿洲土壤Cd-Pb-Zn-Ni复合污染下的油菜盆栽试验,采用Tessier五步连续浸提法探究了重金属复合污染对油菜生长的影响及其各形态的转化归趋和生物有效性。结果显示,随着Cd-Pb-Zn-Ni复合胁迫水平的升高,油菜的干重先增加后减小,根系的生长由促进作用转变为抑制作用;对照土壤中4种重金属元素均以残渣态为主要赋存形态,可交换态的含量均很小;随着外源重金属的添加,油菜种植土壤中4种重金属元素的各形态含量随之增加,Cd、Pb、Zn的可交换态和Ni的碳酸盐结合态对外界胁迫响应强度最大,Cd、Pb、Zn、Ni的活性增加,且Cd、Pb的主要赋存形态迅速转变为碳酸盐结合态和铁锰氧化态,Zn的主要赋存形态由残渣态和碳酸盐结合态过渡到碳酸盐结合态和铁锰氧化态,Ni的主要赋存形态为碳酸盐结合态;Cd、Zn在茎叶中的含量大于根系,Pb、Ni反之,油菜能将Cd、Zn更多的运输至茎叶,Pb、Ni则主要积累在根系;油菜茎叶吸收Cd和油菜各部位吸收Zn的主要贡献形态为可交换态,根吸收Cd的主要贡献形态由可交换态转变为有机结合态,根吸收Pb和油菜各部位吸收Ni的主要贡献形态为碳酸盐结合态。
Rape（Brassica campestris L.） is frequently planted in oasis soils from the Northwest arid areas,and Cd,Pb,Zn,Ni are the common pollutants,which are widely distributed in soil environment.By pot experiments to simulate Cd-Pb-Zn-Ni combined pollution,and using Tessier sequential extraction,this paper studied the effect of Cd-Pb-Zn-Ni combined pollution on the growth of rape,the transformation and tendency of chemical forms of heavy metals in soils,and bioavailability to the rape.Dry weight,root height and the concentration of Cd,Pb,Zn and Ni in different parts of rape was measured after one growing season（66 days）.As Cd-Pb-Zn-Ni combined stress levels rising,the dry weight of rape first increased and then decreased,the growth of root was first promoted and then inhibited.The chemical speciation of heavy metals contains exchangeable form,carbonate bound form,ferric-manganese oxide form,organic matter form and residual form.Cd,Pb,Zn and Ni mainly existed in residual form,while the concentrations of exchangeable form of them were all low in soils for control.With the increasing concentration of exogenous heavy metals,the concentration of various forms of Cd,Pb,Zn and Ni increased in soils.And the fractionation character of heavy metals transformed greatly.The exchangeable form of Cd,Pb,Zn and the carbonate bound form of Ni had the greatest response when the exogenous Cd,Pb,Zn and Ni were added jointly,where rape were planted according to the coefficient of variation（Cv）.Meanwhile,the activeness of Cd,Pb,Zn and Ni enhanced considerably according to mobility factor.Furthermore,the main chemical speciation of Cd and Pb changed from residual form into carbonate bound form and ferric-manganese oxide form rapidly,while the main chemical speciation of Zn changed from residual form and carbonate bound form into carbonate form and ferric-manganese oxide,and the main chemical speciation of Ni changed from residual form into carbonate bound form.The concentration of Cd and Zn in stems and leaves were higher than whic
出处
《生态学报》
CAS
CSCD
北大核心
2013年第2期619-630,共12页
Acta Ecologica Sinica
基金
国家自然科学基金(51178209,91025015)
关键词
重金属
复合污染
形态特征
生物有效性
heavy metals
combined pollution
fractionation character
bioavailability
