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 草原位元素吸收差异

背景和目的北美东部蛇纹石植物群的元素吸收在很大程度上是未知的。本研究的目的是在美国东部具有三种截然不同土壤类型的五个地点（包括三个蛇纹石地点）原位测定三种天然假金属植物 C4 草的土壤和叶片中的主要和微量元素浓度。从五个地点的三个物种的土壤和叶子中测量并关联了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高达五个数量级。来自含金属地点的土壤表现出比非含金属地点更高浓度的特征元素。在含金属的种群中，元素浓度取决于元素。主要元素（Ca、Mg、叶片中的 K) 低于典型的毒性阈值，而 Zn 的浓度更高。结论在草类中，即使土壤浓度较高，物种也可以在其叶片中保持相对较低的金属浓度。然而，在高度受锌污染的土壤中，我们发现了阈值浓度的证据，高于该浓度，锌的吸收急剧增加。最后，在一个地点缺乏蛇纹石土壤的主要特征表明土壤调查和恢复对维持蛇纹石群落和避免土壤侵蚀的重要性。我们发现了阈值浓度的证据，高于该浓度，Zn 吸收急剧增加。最后，在一个地点缺乏蛇纹石土壤的主要特征表明土壤调查和恢复对维持蛇纹石群落和避免土壤侵蚀的重要性。我们发现了阈值浓度的证据，高于该浓度，Zn 吸收急剧增加。最后，在一个地点缺乏蛇纹石土壤的主要特征表明土壤调查和恢复对维持蛇纹石群落和避免土壤侵蚀的重要性。