土壤重金属质量分数对广玉兰地上部重金属积累特征的影响

通过典型选样方法,在永康市城区采集了不同重金属质量分数土壤条件下广玉兰(Magnolia grandiflora Linn)的树叶、树枝、树干以及土壤样品,利用ICP-OES测定植物和土壤中6种重金属(Mn、Cu、Zn、Pb、Cr、Ni)的质量分数,分析比较6种土壤重金属质量分数梯度下广玉兰地上部分各器官对重金属的积累特征。结果表明:广玉兰地上部分重金属质量分数因器官、元素种类不同以及土壤重金属质量分数的不同而存在差异。在6个不同土壤重金属质量分数梯度下,广玉兰体内重金属质量分数由大到小的总体趋势为Mn、Zn、Cr、Cu、Pb、Ni,各器官中重金属质量分数最高是树干,其次是树叶,树枝最弱。玉兰地上部分各器官对重金属元素的富集能力由强到弱依次为树干、树枝、树叶,其中树干对Pb、Ni两种元素表现出了高富集的特征(富集系数BC,F1),富集系数分别达到了1.256和1.188,对Cu、Zn、Pb、Mn、Ni重金属的富集系数随土壤中污染梯度的上升总体呈下降趋势。通过对广玉兰各器官生物量进行估算得出,重金属积累量由大到小的顺序为树干、树叶、树枝,树干在单株广玉兰地上部重金属积累总量中所占比最高,普遍达到60%以上,其中Ni、Pb元素积累量占比高,平均可达84.93%、88.50%。综合考虑广玉兰体内重金属质量分数、富集系数以及积累量,建议可将广玉兰用于Cu、Ni、Pb污染土壤的修复。

Effectso f Soil Heavy Metal Content on Heavy MetalA ccumulation Characteristics in the Upper Part of Magnolia grandiflora L.

The contents of heavy metal ( Mn, Cu, Zn, Pb, Cr, Ni) in leaves, branches, trunk of Magnolia grandiflora L.and rhizosphere soils in Yongkang City were measured by using the Inductively Coupled Plasma Optical Emission Spectroscopy ( ICP-OES ) to compare the heavy metal enrichment characteristics between different heavy metal content gradient through a typical sample method.The contents of heavy metals in different heavy metal mass gradient of M.grandiflora L., the con-tent of the same element in different organs, and that of different elements and different soil heavy metal mass in the same organ were all different.Heavy metal content in M.grandiflora L.was in the descending order of Mn, Zn, Cr, Cu, Pb, and Ni.The heavy metal absorption capacity in above-ground organs was in the descending order of trunk, leaf, and branch.The enrichment capacity of M.grandiflora L.in different organs was in the descending order of trunk, branch, and leaf, the trunk showed high enrichment characteristics of Pb (1.256) and Ni (1.188) (BCF>1).The heavy metal enrich-ment coefficient of Mn,Cu, Zn, Pb, Ni in M.grandiflora L.as the rise of the pollution in the soil gradient decreases with a significant negative correlation.The heavy metal accumulation in above-ground organs was in the descending order of trunk, leaf, and branch.Trunk accounted for more than 60％, and the Pb, Ni element accumulation in the highest propor-tion with the average of 88.50％and 84.93％, respectively.Comprehensively considering the contents of heavy metals, en-richment coefficient and accumulation in M.grandiflora L.were suitable for remediation of soils contaminated by Cu, Ni, and Pb.