Background and aimsElemental uptake in serpentine floras in eastern North America is largely unknown. The objective of this study was to determine major and trace element concentrations in soil and leaves of three native pseudo-metallophyte C4 grasses in situ at five sites with three very different soil types, including three serpentine sites, in eastern USA.MethodsPseudo-total and extractible concentrations of 15 elements were measured and correlated from the soils and leaves of three species at the five sites.ResultsElement concentrations in soils of pseudo-metallophytes varied up to five orders of magnitude. Soils from metalliferous sites exhibited higher concentrations of their characteristic elements than non-metalliferous. In metallicolous populations, elemental concentrations depended on the element. Concentrations of major elements (Ca, Mg, K) in leaves were lower than typical toxicity thresholds, whereas concentrations of Zn were higher.ConclusionsIn grasses, species can maintain relatively low metal concentrations in their leaves even when soil concentrations are richer. However, in highly Zn-contaminated soil, we found evidence of a threshold concentration above which Zn uptake increases drastically. Finally, absence of main characteristics of serpentine soil at one site indicated the importance of soil survey and restoration to maintain serpentinophytes communities and avoid soil encroachment.

中文翻译：

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美国东部三种假金属植物 C4 草的元素吸收差异


背景和目标北美东部蛇纹石植物群的元素吸收很大程度上未知。本研究的目的是确定美国东部五个具有三种截然不同土壤类型的地点（包括三个蛇纹石地点）的三种本地假金属植物 C4 草的土壤和叶子中的主要和微量元素浓度。对五个地点的三个物种的土壤和叶子测量并关联了 15 种元素的可提取浓度。结果假金属植物土壤中的元素浓度变化达五个数量级。含金属地点的土壤比非金属地点的土壤表现出更高浓度的特征元素。在金属族中，元素浓度取决于元素。叶片中主要元素（Ca、Mg、K）的浓度低于典型的毒性阈值，而Zn的浓度较高。结论在草类中，即使土壤浓度较高，物种也能在其叶片中保持相对较低的金属浓度。然而，在锌高度污染的土壤中，我们发现了阈值浓度的证据，高于该阈值浓度时锌的吸收量急剧增加。最后，一处蛇纹土主要特征的缺乏表明了土壤调查和恢复对于维持蛇纹植物群落和避免土壤侵蚀的重要性。