School of Plant Biology, Faculty of Science, The University of Western Australia, 35 Stirling Highway, Crawley (Perth), WA, 6009, Australia.
Oecologia. 2014 Jan;174(1):23-31. doi: 10.1007/s00442-013-2747-z. Epub 2013 Aug 10.
Species that inhabit phosphorus- (P) and micronutrient-impoverished soils typically have adaptations to enhance the acquisition of these nutrients, for example cluster roots in Proteaceae. However, there are several species co-occurring in the same environment that do not produce similar specialised roots. This study aims to investigate whether one of these species (Scholtzia involucrata) can benefit from the mobilisation of P or micronutrients by the cluster roots of co-occurring Banksia attenuata, and also to examine the response of B. attenuata to the presence of S. involucrata. We conducted a greenhouse experiment, using a replacement series design, where B. attenuata and S. involucrata shared a pot at proportions of 2:0, 1:2 and 0:4. S. involucrata plants grew more in length, were heavier and had higher manganese (Mn) concentrations in their young leaves when grown next to one individual of B. attenuata and one individual of S. involucrata than when grown with three conspecifics. All S. involucrata individuals were colonised by arbuscular mycorrhizal fungi, and possibly Rhizoctonia. Additionally, P concentration was higher in the young leaves of B. attenuata when grown with another B. attenuata than when grown with two individuals of S. involucrata, despite the smaller size of the S. involucrata individuals. Our results demonstrate that intraspecific competition was stronger than interspecific competition for S. involucrata, but not for B. attenuata. We conclude that cluster roots of B. attenuata facilitate the acquisition of nutrients by neighbouring shrubs by making P and Mn more available for their neighbours.
栖息在磷（P）和微量元素贫瘠土壤中的物种通常具有增强获取这些养分的适应能力，例如 Proteaceae 中的簇生根。然而，在同一环境中也有几种不产生类似特化根的物种共存。本研究旨在探讨其中一种物种（Scholtzia involucrata）是否可以受益于共存的 Banksia attenuata 的簇生根对 P 或微量元素的动员，以及研究 B. attenuata 对 S. involucrata 存在的反应。我们进行了一项温室实验，采用替代系列设计，B. attenuata 和 S. involucrata 在一个盆中以 2:0、1:2 和 0:4 的比例共享。当与一个 B. attenuata 和一个 S. involucrata 个体一起生长时，S. involucrata 植物的长度生长更多，重量更重，其幼叶中的锰（Mn）浓度更高，而当与三个同种个体一起生长时则更低。所有 S. involucrata 个体都被丛枝菌根真菌和可能的 Rhizoctonia 定殖。此外，当与另一个 B. attenuata 一起生长时，B. attenuata 的幼叶中 P 浓度更高，而当与两个 S. involucrata 个体一起生长时则更低，尽管 S. involucrata 个体的体积较小。我们的结果表明，同种竞争对 S. involucrata 比对 B. attenuata 更强，但对 B. attenuata 则不然。我们得出的结论是，B. attenuata 的簇生根通过使 P 和 Mn 更易为其邻居获取，从而促进了邻近灌木对养分的获取。
