两年倾斜生长杨树吸收和富集土壤镉特性研究

Study on the Uptake and Enrichment of Cd from Soil in Two-year Old Poplar Trees Under Leaning Plantation

杨树是提取修复重金属镉(Cd)的优势树种,应拉木特殊的微结构特征可能会有利于重金属在树干木材部分的附着聚集。这里选择69杨(Populus deltoides ‘Lux’ (I-69/55)),通过盆栽实验,着眼全树、聚焦树干,研究在外源Cd胁迫下两年生人工倾斜(45°)种植杨树生长及吸收与富集Cd的特性。结果表明,Cd对两年倾斜杨树生长没有显著影响,杨树不同部位Cd含量均随土壤中Cd处理浓度的增加而增加,表现出对Cd有较强的耐受性。树叶中Cd含量和富集能力均最高,其次是树皮、树根、树枝、树干,树叶和树干的平均富集系数分别为1.45和0.58。对于树干,纵向上,树干顶部Cd镉含量显著高于中部和基部;横向上,木材对应区Cd含量略高于应拉区,近树皮处Cd含量显著高于近髓心处。

Poplar is the dominant tree species in the dendroremedration of Cd.Tension wood has some microstructure features,such as the colloidal layer and large micropores in cell wall,which may be conducive to the accumulation of heavy metals.Poplar 69 (Populus deltoides ‘Lux’ (I-69-55)) was selected to study the uptake and enrichment characteristics of Cd in the two-year old leaning planted (45°) poplar trees with a focus on the trunk wood through pot experiment.The results showed that Cd had no significant effect on the growth of the poplar trees,and the Cd content in different parts of poplar increased with the increase of Cd concentration in soil.The cadmium content and enrichment ability of leaves were the highest,followed by bark,roots,branches and trunks,with the average enrichment coefficient of leaves and trunks being 1.45 and 0.58,respectively.In the trunk wood,longitudinally,the Cd content in the top trunk wood was significantly higher than that at the middle and base heights.Radially,the Cd content in the opposite zone was slightly higher than that in the tension zone,and that in the wood near the bark was significantly higher than that near the pith.