Faghihinia Maede, Jansa Jan
Laboratory of Fungal Biology, Institute of Microbiology, Czech Academy of Sciences, Praha, Czechia.
Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, United States.
Front Plant Sci. 2022 Dec 15;13:1047270. doi: 10.3389/fpls.2022.1047270. eCollection 2022.
Plant-plant interactions and coexistence can be directly mediated by symbiotic arbuscular mycorrhizal (AM) fungi through asymmetric resource exchange between the plant and fungal partners. However, little is known about the effects of AM fungal presence on resource allocation in mixed plant stands. Here, we examined how phosphorus (P), nitrogen (N) and carbon (C) resources were distributed between coexisting con- and heterospecific plant individuals in the presence or absence of AM fungus, using radio- and stable isotopes. Congeneric plant species, and , inoculated or not with , were grown in two different culture systems, mono- and mixed-species stands. Pots were subjected to different shading regimes to manipulate C sink-source strengths. In monocultures, gained more mycorrhizal phosphorus uptake benefits than . However, in the mixed culture, the AM fungus appeared to preferentially transfer nutrients (P and N) to compared to . Further, we observed higher C allocation to mycorrhiza by in mixed- compared to the mono-systems, which likely contributed to improved competitiveness in the mixed cultures of vs. regardless of the shading regime. Our results suggest that the presence of mycorrhiza influenced competitiveness of the two species in mixed stands in favor of those with high quality partner, , which provided more C to the mycorrhizal networks. However, in mono-species systems where the AM fungus had no partner choice, even the lower quality partner (i.e., ) could also have benefitted from the symbiosis. Future research should separate the various contributors (roots vs. common mycorrhizal network) and mechanisms of resource exchange in such a multifaceted interaction.
植物与植物之间的相互作用和共存可以通过共生丛枝菌根（AM）真菌，经由植物与真菌伙伴之间的不对称资源交换直接介导。然而，关于AM真菌的存在对混生植物群落中资源分配的影响，我们所知甚少。在此，我们使用放射性和稳定性同位素，研究了在有或没有AM真菌的情况下，磷（P）、氮（N）和碳（C）资源如何在共存的同种和异种植物个体之间分配。将接种或未接种AM真菌的同属植物物种和种植在两种不同的培养系统中，即单物种群落和混合物种群落。对花盆进行不同的遮荫处理，以控制碳源库强度。在单作中，比获得更多的菌根磷吸收益处。然而，在混合培养中，与相比，AM真菌似乎优先向转移养分（P和N）。此外，我们观察到，与单作系统相比，在混合系统中向菌根分配了更多的碳，这可能有助于在与的混合培养中提高竞争力，而与遮荫处理无关。我们的结果表明，菌根的存在影响了两种植物在混合群落中的竞争力，有利于那些有高质量伙伴（即向菌根网络提供更多碳的）的植物。然而，在AM真菌没有伙伴选择的单物种系统中，即使是质量较低的伙伴（即）也能从共生关系中受益。未来的研究应该在这种多方面的相互作用中，区分各种贡献者（根系与共同的菌根网络）以及资源交换的机制。
