【摘要】 我们通过温室盆栽试验 ,在不同Cd处理的土壤中加入EDTA ,分析了印度芥菜根和地上部Cd的浓度 ,探讨EDTA进入土壤后对Cd吸收和运输的影响。结果表明 :加入EDTA ,水提取的Cd浓度增加了 40 0倍以上 ,NH4 NO3提取的Cd浓度增加了 40倍以上 ,在土壤Cd浓度较低时 ,EDTA对植物吸收Cd没有显著影响 ,当土壤添加Cd在 1 3 0mgkg- 1以上时 ,加入EDTA显著增加了地上部Cd的浓度。EDTA能增加印度芥菜地上部中Cd的浓度 ,不是由于土壤溶液中Cd浓度增加从而增加了印度芥菜根对Cd的吸收 ,可能是EDTA加入土壤后增加了这些元素在土壤溶液中的浓度 ,从而高浓度的Cd对植物根细胞产生毒害 ,增加了细胞膜的透性后 ,土壤溶液中的络合物得以进入根细胞并随蒸腾作用运输到地上部。更多还原

【Abstract】 Summary There are two theories for cation EDTA uptake: One suggested that metal EDTA complex formed in the soil could increase metal solubility, and promote diffusion, and, hence, elevate potential uptake. Another theory suggested the complexation of metals with EDTA reduced the activities of free ions in the soil solution, and, therefore, decreased uptake. Pot experiment was conducted to study the role of EDTA in cadmium absorption by Indian Mustard ( Brassica juncea ). H 2O and NH 4NO 3 extractable Cd increased sharply in soils receiving EDTA treatment. Cadmium accumulation in the roots of B. juncea decreased significantly after EDTA application. However, Cd in shoots increased significantly when Cd added was over 130 mg kg -1 in soils, and Cd toxicity was observed. The results suggested that Cd concentration increased in soil solution after addition of EDTA, which resulted in increasing absorption and translocation when plant was suffering from toxicity.更多还原