Cd/Pb胁迫下油菜中重金属的分布、富集及迁移特征

Distribution,enrichment and migration characteristics of heavy metals in rape under Cd/Pb stress

采用盆栽试验,研究了干旱区绿洲土壤Cd/Pb复合胁迫下重金属在油菜中的分布、富集及迁移规律.结果表明:较低水平的Cd/Pb复合胁追水平(ω(Cd)<1.40×10^(-6),ω(Pb)<300×10^(-6))对油菜的生长具有促进作用,超过此临界值后具有逐渐增大的抑制作用;油菜各部位的重金属质量分数均与土壤中相应元素的胁迫水平呈显著正相关,均随着复合胁迫水平的增加而增加,吸收和迁移模式均为二次项;油菜不同部位对Cd,Pb的富集能力和迁移能力存在差异,对于Cd,茎叶富集能力较大,而对于Pb,根系富集能力较大;转运能力为Cd大于Pb,油菜能将根系吸收的Cd更多地转运到茎叶,而同时也将更多的Pb滞留在了根中.

A pot experiment for the distribution, accumulation and migration of heavy metals in the rape was conducted in arid area oasis soil under Cd and Pb combined stress. The results showed that a lower level of Cd/Pb composite stress levels （w（Cd）〈l.40×l0-8, ω（Pb）〈300×l0-6） could promote the growth of rape, but beyond this critical value it would lead to increased inhibition. The heavy metal content in different parts of rape and the concentrations of the corresponding element of coercion in soil showed a significant positive correlation. The content of heavy metals in different parts of rape was increasing with the Cd, Pb combined stress level. The absorption and transport models were quadratic. The enrichment and migration capabilities of Cd and Pb were different in different parts of rape, with the enrichment capability of stems and leaves of Cd being greater, and for Pb it was greater in the roots. The transport capacity of Cd was greater than Pb, and the roots of rape could transfer more Cd to stems and leaves, while more Pb also remained in the root.