摘要
采用盆栽试验及连续浸提形态分级方法,研究了Cd和Pb在土壤中的形态分布规律及其对油菜的生物有效性的影响。结果表明,当土壤受外源Cd/Pb污染后,重金属的形态分布特征发生了变化,以可交换态(EXC)响应最大,Cd、Pb的赋存形态分别以碳酸盐结合态(CAB)、铁锰氧化态(FMO)和碳酸盐结合态(CAB)为主;一定浓度范围内的Cd/Pb复合胁迫能促进油菜的生长,油菜根系和茎叶的Cd、Pb含量均随着Cd/Pb复合胁迫水平的升高而持续增加。茎叶中的Cd含量远远高于根系,Pb含量反之。油菜可将更多的Cd从根系转移至茎叶,而将更多的Pb滞留在根系中;对油菜根系吸收Cd最重要的形态为可交换态(EXC)和碳酸盐结合态(CAB),而对茎叶吸收Cd以及油菜吸收Pb贡献最大的则为碳酸盐结合态(CAB)。
Pot experiment and Tessier sequential extraction were conducted to study the speciation of Cd and Pb forms and their bioavailability in rape（Brassica campestris L. ） in the oasis soils. The results showed that after soil polluted by selected heavy metals, the distribution of their chemical forms changed in soil after pollution by Cd and Pb, and the largest response was exchangeable form of Cd. Cd existed mainly in carbonate-form, while Pb mainly in carbonate-form and Fe-Mn oxide bound form. The combined stress with Cd/Pb in a certain range could promote the growth of rape. Cd/Pb content in rape roots and shoots increased with increasing combined stress concentration in soils. Cd con- tent in stems and leaves was much higher than that in roots, and Pb was exactly the opposite. Rape could transfer most Cd from roots to stems and leaves, while the great part of Ph remain in roots. The exchangeable form and carbonate-form made the most contribution to the content of Cd in roots, while carbonate-form made the most contribution to the content of Cd in stems and leaves, and Pb in rape.
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2012年第6期1089-1096,共8页
Journal of Agro-Environment Science
基金
国家自然科学基金(NSFC51178209,NSFC91025015)
关键词
镉
铅
形态分布
化学形态
生物有效性
cadmium
lead
speciation distribution
chemical forms
bioavailability
