Background and Aims

In tropical ultramafic soils, potassium (K) is typically the most growth limiting nutrient. However, tropical nickel (Ni) hyperaccumulator plants, including Phyllanthus rufuschaneyi and Rinorea cf. bengalensis (which are ‘metal crops’ used in agromining) from Malaysia, have unusually high K shoot accumulation compared to other species, despite naturally growing on severely K-impoverished ultramafic soils. This study aimed to establish the response to soil K availability in relation to uptake of K and other elements in the roots and shoots of P. rufuschaneyi and R. cf. bengalensis.

Methodology

We undertook an experiment in which soluble K was dosed to ultramafic soil in pots with P. rufuschaneyi and R. cf. bengalensis in Sabah (Malaysia).

Results

The results show that root K concentrations increased markedly as the soil K availability increased by 35-fold, whilst the corresponding effect on K accumulation in the shoots of P. rufuschaneyi and R. cf. bengalensis was not significantly different in relation to soil K dosing. Observed divergent responses between root and shoot K accumulation in these species suggests a separate genetic control of K uptake and xylem loading in P. rufuschaneyi and R. cf. bengalensis.

Conclusion

The tight control of root-to-shoot K translocation and constrained K accumulation in shoots under a soil K gradient is likely an adaptive mechanism to the evolution of these species to grow in highly nutrient-impoverished ultramafic soils. This study provides information that will be useful for better nutrient management of tropical Ni metal farms that use K-efficient Ni ‘metal crops’.

中文翻译：

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热带“金属作物”离子组对土壤钾素有效性的响应

背景和目标

在热带超镁铁质土壤中，钾（K）通常是最限制生长的养分。但是，热带镍（Ni）超富集植物，包括费兰（Phyllanthus rufuschaneyi）和里诺里亚（Rinorea）参见。孟加拉从马来西亚（其在使用agromining“金属作物”） ，具有不寻常的高K值拍累积相比于其它物种，尽管严重K-贫困超镁铁土壤自然生长。这项研究旨在建立对土壤钾有效性的响应，该关系与P. rufuschaneyi和R. cf.的根和芽中的K和其他元素的吸收有关。孟加拉。

方法

我们进行了一项实验，在该实验中，将可溶性K施用到 rufuschaneyi和R. cf. 沙巴（马来西亚）的孟加拉。

结果

结果表明，随着土壤钾素利用率增加35倍，根系K含量显着增加，而对P. rufuschaneyi和R. cf的芽中K积累的影响相应。孟加拉邦在土壤钾肥施用方面无显着差异。在这些物种的根和茎中钾积累之间观察到的不同反应表明，对P. rufuschaneyi和R. cf.的钾吸收和木质部负载有单独的遗传控制。孟加拉。

结论

在土壤钾梯度下，严格控制根茎到钾素的转运和限制芽中钾素的积累，可能是这些物种进化在营养贫瘠的超镁铁质土壤中生长的一种适应机制。这项研究提供的信息将有助于更好地管理使用钾效率高的镍“金属作物”的热带镍金属农场的养分管理。