College of Life Sciences, Nanjing Agricultural University, Nanjing, People's Republic of China.
Chemosphere. 2010 Feb;78(9):1136-41. doi: 10.1016/j.chemosphere.2009.12.030. Epub 2010 Jan 13.
The concentrations of heavy metals in Phytolacca americana L. and corresponding soil samples from three contaminated sites and an uncontaminated site were studied. Hydroponic experiments were also conducted to investigate the Cd uptake ability and mechanism of P. americana. The field results showed that the average Cd concentration was 42 mg kg(-1) in P. americana leaves, with the highest concentration of 402 mg kg(-1) found at Datianwan. A significant relationship was observed between the concentrations of Cd in leaves and those of corresponding soils on a logarithmic scale. Under laboratory hydroponic conditions, the maximum Cd concentration in aerial tissues of P. americana was 637 mg kg(-1), under treatment with 100 microM Cd. The population from the uncontaminated site (Zijinshan) also had a remarkable ability to accumulate Cd in shoots to concentrations well in excess of 100 microM in the hydroponic experiment, similar to the population from contaminated site, suggesting that Cd accumulation is a constitutive trait of P. americana. In the presence of 100 microM Cd, the addition of polyethylene glycol decreased leaf transpiration, the shoot Cd concentration, and the shoot/root Cd concentration ratio. There was a significantly positive relationship between the shoot Cd concentration and the leaf transpiration of P. americana. A similar significant positive correlation was also obtained between the shoot/root Cd concentration and leaf transpiration. Moreover, pretreatment with 5 microM abscisic acid or 5 microM HgCl(2) significantly decreased the Cd concentration in P. americana shoots. These results suggest that transpiration has an important role in Cd accumulation in shoots of P. americana.
研究了来自三个污染地点和一个未污染地点的美洲商陆（Phytolacca americana L.）及其相应土壤样本中的重金属浓度。还进行了水培实验以研究美洲商陆对 Cd 的吸收能力和机制。田间结果表明，美洲商陆叶片中的 Cd 平均浓度为 42mg/kg，在大田湾最高浓度为 402mg/kg。叶片中 Cd 浓度与对应土壤中 Cd 浓度之间呈对数关系。在实验室水培条件下，当用 100μM Cd 处理时，美洲商陆地上组织中的 Cd 最大浓度为 637mg/kg。来自未污染地点（紫金山）的种群在水培实验中也具有将 Cd 积累到超过 100μM 的 shoots 中显著能力，类似于污染地点的种群，表明 Cd 积累是美洲商陆的一种组成特征。在 100μM Cd 存在下，添加聚乙二醇会降低叶片蒸腾、地上部 Cd 浓度和 shoot/root Cd 浓度比。美洲商陆叶片蒸腾与 shoot Cd 浓度之间存在显著正相关关系。在 shoot/root Cd 浓度与叶片蒸腾之间也获得了类似的显著正相关关系。此外，用 5μM 脱落酸或 5μM HgCl2 预处理会显著降低美洲商陆 shoot 中的 Cd 浓度。这些结果表明蒸腾在美洲商陆 shoot 中 Cd 积累中起重要作用。
