不同生态型东南景天对土壤中Cd的生长反应及吸收积累的差异性  

GROWTH RESPONSE AND UPTAKE DIFFERENCES BETWEEN TWO ECOTYPES OF SEDUM ALFREDII TO SOILS Cd

作　　者：龙新宪[1] 王艳红[1] 刘洪彦[1] 

机构地区：[1]华南农业大学资源环境学院,广州510642

出　　处：《植物生态学报》2008年第1期168-175,共8页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(20407008)

摘　　要：采用盆栽方法研究了两种生态型东南景天(Sedum alfredii)对土壤中不同含量Cd(即对照,12.5,25,50,100,200,300,400mg.kg-1)的生长反应、吸收和积累Cd的差异性。结果表明,土壤添加重金属Cd后,矿山生态型东南景天生长正常,地上部和根系Cd含量随着土壤中Cd含量的增加而增加,在400mg.kg-1Cd处理下含量分别高达2900和500mg.kg-1,其地上部显著大于根部;然而,土壤添加Cd后,非矿山生态型东南景天的生长受到抑制,地上部和根部的生物量显著降低。当土壤Cd含量为50～100mg.kg-1时,非矿山生态型东南景天的地上部和根系Cd含量随着土壤中Cd含量的增加而增加,而且根系Cd含量则大于地上部。当土壤Cd≤50mg.kg-1时,矿山生态型东南景天根系Cd含量比非矿山生态型高,但当土壤Cd≥100mg.kg-1,两者之间无显著差异;然而,但在同一Cd处理水平下,矿山生态型东南景天地上部Cd含量总是高于非矿山生态型。这些结果表明,矿山生态型东南景天有很强的忍耐和吸收土壤Cd的能力,再次证明其为一种Cd超积累植物。Aims Our objective was to compare growth responses to soil Cd, as well as Cd uptake and accumulation in two ecotypes of Sedum alfredii. Methods In a pot experiment, we planted one mining ecotype of S. alfredii and one non-mining ecotype in eight soils with different Cd levels （control, 12.5, 25, 50, 100,200,300,400 mg·kg^-1） for two successive croppings. Important findings The mining ecotype of S. alfredii grew healthy at all Cd supply levels. Its Cd concentrations in shoots and roots linearly increased with increasing soil Cd levels and reached a maximum of approximately 2 900 mg·kg^-1（DW） and 500 mg·kg^-1 at 400 mg·kg^-1 treatment, respectively. Its Cd concentration in shoots were far higher than roots. In contrast, the growth of the non-mining ecotype was severely inhibited by soil Cd supply, as its shoot and root biomass significantly decreased compared with the control treatment. Cd concentrations in shoots and roots of the non-mining ecotype also increased with increasing soil Cd levels, but its Cd concentration in roots was higher than in shoots. At low soil Cd levels （ ≤ 50 mg·kg^-1）, Cd concentration in roots of the mining ecotype was higher than the non-mining ecotype, while there were no significant differences between the two ecotypes at high Cd levels （ 100 and 200 mg·kg^- 1）. Increasing soil Cd levels from 0 to 400 mg ·kg^-1 enhanced Cd concentration in shoots of the two ecotypes, and Cd concentration in shoots of the mining ecotype was always far higher than the non-mining ecotype at all Cd supply levels. These results indicate that the mining ecotype of S. alfiedii has an extraordinary ability to tolerate and uptake Cd from soil and is proved to be a Cd hyper-accumulator.

关 键 词：东南景天 镉 超积累 土壤污染 生态修复 

分 类 号：Q945[生物学—植物学]