Cd-Cu-Pb复合污染对芥菜吸收Cd、Cu和Pb及矿质元素的影响

以十字花科的芥菜为材料,通过室内盆栽均匀设计试验,研究了Cd-Cu-Pb复合污染下芥菜对重金属的吸收转运特点以及对矿质元素吸收的影响.结果表明:3种重金属在芥菜体内积累能力为Cd>Cu>Pb;芥菜对Pb、Cd有较强耐性,对高浓度Cu耐性不强.土壤中重金属的含量是影响芥菜各部分重金属含量的主要因素之一;Cd可抑制芥菜对Pb的吸收和转移,促进Cu向芥菜地上部转移;Cd-Pb复合效应促进了Cd在芥菜体内累积;Cu抑制芥菜吸收Pb;Cu-Pb可促进Cd抑制Cu在芥菜各部的积累.与对照相比,复合污染显著降低了芥菜对矿质元素的吸收累积,各处理芥菜对Mg、Fe和K的吸收转移特点显示出相似的规律,即地上部w(Mg)远大于地下部而w(Fe)和w(K)为地下部占优.Cd可极大促进芥菜对K的吸收而抑制对Fe的吸收,Cu则阻碍地下部对K的吸收;Cu与Cd-Pb复合效应可抑制K向地上部转移.

Effects of Cd-Cu-Pb Compound Contamination on Absorption of Cd, Cu, Pb and Mineral Elements in Mustard

The effects of Cd-Cu-Pb compound pollution on the absorption and enrichment characteristics of heavy metals by one kind of cruciferous mustard were studied.The absorption characteristics of mineral elements were also investigated.The results indicate that the absorption and accumulation of heavy metals in the mustard decreased in the order of Cd>Cu>Pb.The mustard showed a strong tolerance to Cd and Pb,but not to the stress of high Cu.The concentrations of heavy metals in the soil were the key factors influencing concentrations of heavy metals in the various parts of the mustard.Cd inhibited the absorption and transportation of Pb in the mustard,but increased the transport of Cu to the aboveground parts of the mustard.The combination of Cd-Pb promoted the enrichment of Cd in various parts of the mustard.Cu significantly inhibited the absorption of Pb.Cu-Pb increased the enrichment of Cd,but inhibited the accumulation of Cu in the mustard.As compared with the control treatment,the combined pollution significantly reduced the content of mineral elements in various parts of the mustard.Similar absorption and transportation behavior of Mg,Fe and K by the mustard were found among all treatments: the concentration of Mg in the shoots was much higher than that in the roots,while Fe and K were mainly accumulated in the roots;Cd greatly increased the absorption of K while inhibiting the absorption of Fe;Cu inhibited the absorption of K in the underground parts of the mustard;and,Cu and Cd-Pb decreased K transport from the roots to the shoots of the mustard.