Wei Shuhe, Zhou Qixing, Mathews Shiny
Key Laboratory of Terrestrial Ecological Process, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, PR China.
J Hazard Mater. 2008 Nov 30;159(2-3):544-7. doi: 10.1016/j.jhazmat.2008.02.052. Epub 2008 Feb 23.
Identification of hyperaccumulator and accumulator is still key step of phytoextracting-contaminated soils by heavy metals. In a former published experiment, Taraxacum mongolicum showed basic characteristics of hyperaccumulators. In order to confirm if this plant was a Cd-hyperaccumulator, concentration gradient experiment and sample-analyzing experiments were designed and performed. The results showed that Cd enrichment factor and Cd transformation factor of T. mongolicum were all higher than 1 in concentration gradient experiment. The shoot biomasses did not reduced significantly (p<0.05) compared with the control without Cd added under the conditions of lower than 25 mgkg(-1) Cd spiked into soil. However, Cd concentration in shoot of T. mongolicum was not higher than 100 mgkg(-1) the minimum a Cd-hyperaccumulator should have under the conditions of any concentration level of Cd spiked. Thus, T. mongolicum should be a Cd-accumulator. In the sample-analyzing experiments settled in a Pb-Zn mine area and Shenyang wastewater irrigation region, T. mongolicum also showed that Cd-accumulator characteristics. Based on these results, T. mongolicum could be identified as a Cd-accumulator, which may have important implication in plant physiology and gene engineering.
确定超富集植物和富集植物仍然是利用植物提取修复重金属污染土壤的关键步骤。在之前发表的一项实验中，蒲公英表现出了超富集植物的基本特征。为了确定这种植物是否为镉超富集植物，设计并进行了浓度梯度实验和样本分析实验。结果表明，在浓度梯度实验中，蒲公英的镉富集系数和镉转运系数均高于1。在土壤中添加镉浓度低于25 mgkg(-1) 的条件下，与未添加镉的对照相比，地上部生物量没有显著降低（p<0.05）。然而，在任何添加镉浓度水平的条件下，蒲公英地上部的镉浓度均不高于镉超富集植物应具备的最低浓度100 mgkg(-1)。因此，蒲公英应是一种镉富集植物。在铅锌矿区和沈阳污灌区进行的样本分析实验中，蒲公英也表现出了镉富集植物的特征。基于这些结果，蒲公英可被确定为镉富集植物，这可能在植物生理学和基因工程方面具有重要意义。
