[目的]乔木对重金属具有富集能力，但是目前对其积累特征尚不明确，一定程度上限制了乔木修复重金属污染土壤技术的推广应用。探讨5种乔木绿化树种对镉的富集特征。[方法]分析了镉污染土壤上栽植的泡桐Paulownia fortunei、楸树 Catalpa bungei、悬铃木 Platanus acerifolia、黑杨 Populus nigra 和垂柳 Salix babylonica 等树木不同部位对镉的富集特征，并分析了不同树种对镉的积累总量。[结果]供试树种对镉均具有一定的积累能力，单株对镉的积累量为43。01～886。28 mg·株-1，其中垂柳对镉的积累总量最大，达886。28 mg·株-1;其次是黑杨，达392。51 mg·株-1。不同树种不同部位对镉的富集能力也不同，泡桐、楸树、悬铃木、黑杨和垂柳不同部位的富集系数分别为0。07～0。56、0。10～1。24、0。06～1。04、0。32～1。58、0。06～0。97。其中黑杨多数部位(除茎皮外)的富集系数均大于其他树种。所有树种根皮、茎皮和枝皮的镉质量分数均显著(P＜0。05)大于其对应的根材、茎材和枝材。所有树种不同部位镉质量分数与土壤镉质量分数均呈极显著正相关(P＜0。01)。[结论]乔木主要将镉积累到枝部和茎部，其中泡桐、楸树和悬铃木主要积累在枝部，黑杨和垂柳主要积累在茎部。此外，黑杨和垂柳具有较高的镉积累量，是今后镉污染土壤修复中的首选树种。图5表2参23
Cd accumulation characteristics of different greening tree species
[Objective]While trees can accumulate heavy metals,their accumulation characteristics are currently unclear;this,to some degree,restricts the application of the technology of using trees to remediate heavy metal-contaminated soil.This study was designed to explore the cadmium(Cd)accumulation capacities of five greening tree species.[Method]The Cd accumulation characteristics of different parts of various greening trees(Paulownia fortunei,Catalpa bungei,Platanus acerifolia,Populus nigra,and Salix babylonica)planted in Cd-contaminated soil were analyzed,and the total amounts of Cd in the trees were determined.[Result]All the tested trees had a certain Cd accumulation capacity,and the cumulative amount of Cd per tree ranged from 43.01 to 886.28 mg·plant-1.Among the trees,S.babylonica had the highest accumulation amount of Cd(886.28 mg·plant-1),followed by Populus nigra(392.51 mg·plant-1).The Cd accumulation ability varied among different tree species and parts,with concentration coefficients ranging from 0.07 to 0.56,0.10 to 1.24,0.06 to 1.04,0.32 to 1.58,and 0.06 to 0.97 for different parts of Paulownia fortunei,C.bungei,Platanus acerifolia,Populus nigra,and S.babylonica,respectively.The concentration coefficients of most parts(except for the stem bark)of Populus nigra were higher than those of the other trees.The Cd concentrations in the root bark,stem bark,and branch bark of all trees were significantly higher than those in their corresponding root wood,stem wood,and branch wood(P＜0.05).A highly significant positive correlation was found between the Cd contents in different parts of trees and those in the soil(P＜0.01).[Conclusion]The tested tree species accumulated Cd mainly in their branches and stems.Paulownia fortunei,C.bungei,and Platanus acerifolia accumulated Cd mainly in their branches,while Populus nigra and S.babylonica accumulated Cd mainly in their stems.Populus nigra and S.babylonica displayed higher Cd concentrations,which are the preferred tree species for the remediation of Cd-contaminated soil.[Ch,5 fig.2 tab.23 ref.]
treescadmiumtotal amount of accumulationconcentration coefficientsoil remediation
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