Cd、Pb投加浓度对其在黑土中化学形态分布及油菜生长和吸收Cd、Pb的影响

采用室内模拟实验和连续形态分级方法研究了Cd、Pb投加浓度对其在黑土中化学形态分布及油菜生长和吸收Cd、Pb量的影响.结果表明:随Cd、Pb投加量的增加,土壤中Cd交换态含量增幅较大,Pb碳酸盐结合态、Fe-Mn氧化物结合态含量增幅较大;外源Cd在土壤中的存在形态以交换态和残留态为主,Pb的交换态比例相对较低,其存在形态主要为残留态;土壤Cd、Pb投加浓度较低时,促进了油菜的生长,投加浓度较高时,对油菜生长的抑制作用较为明显;地下部分Cd、Pb含量远高于地上部分,与Cd相比,Pb向地上部的迁移率相对较小;土壤中Cd、Pb各形态含量与油菜地下、地上部分吸收的Cd、Pb量均呈显著正相关,与干质量呈负相关;交换态Cd、Pb对油菜干质量影响最大,碳酸盐结合态对油菜吸收Cd、Pb的贡献最大.

Effects of added concentrations of Cd and Pb on the distribution of Cd and Pb forms in black soil of northeast China and on the Cd and Pb uptake by cole

With pot culture and sequential extraction,this paper studied the effects of different added concentrations of cadmium(Cd) and lead(Pb) on the distribution of Cd and Pb forms in black soil and on the Cd and Pb uptake by cole plant.The results showed that with the increasing concentration of added Cd and Pb,there was a remarkable increase in the contents of exchangeable Cd and carbonate-and Fe-Mn oxide-bound Pb in soil.The exogenous Cd in soil was mainly existed in residual and exchangeable forms,while Pb was mainly in residual form but relatively low in exchangeable form.Lower concentration of added Cd and Pb had positive effects on cole growth,while their higher concentration inhibited the growth significantly.The concentrations of Cd and Pb were greater in root than in shoot,and less Pb was transferred to shoot,compared with Cd.The contents of all forms Cd and Pb in soil were positively correlated with those in cole shoot and root,but negatively correlated with cole dry mass.Among all the chemical forms of Cd and Pb,exchangeable form played an important role in the decrease of cole dry mass,and carbonate-bound form contributed most to the absorption of Cd and Pb by cole.