Plants involved in the arbuscular mycorrhizal (AM) symbiosis trade photosynthetically derived carbon for fungal‐provided soil nutrients. However, little is known about how plant light demand and ambient light conditions influence root‐associating AM fungal communities. We conducted a manipulative field experiment to test whether plants’ shade‐tolerance influences their root AM fungal communities in open and shaded grassland sites. We found similar light‐dependent shifts in AM fungal community structure for experimental bait plant roots and the surrounding soil. Yet, deviation from the surrounding soil towards lower AM fungal beta‐diversity in the roots of shade‐intolerant plants in shade suggested preferential carbon allocation to specific AM fungi in conditions where plant‐assimilated carbon available to fungi was limited. We conclude that favourable environmental conditions widen the plant biotic niche, as demonstrated here with optimal light availability reducing plants’ selectivity for specific AM fungi, and promote compatibility with a larger number of AM fungal taxa.

中文翻译：

---

植物的光照可用性和光照需求在其根部塑造丛枝菌根真菌群落

参与丛枝菌根 (AM) 共生的植物将光合作用衍生的碳交换为真菌提供的土壤养分。然而，关于植物光需求和环境光条件如何影响与根相关的 AM 真菌群落知之甚少。我们进行了操纵性田间试验，以测试植物的耐荫性是否会影响其在开阔和阴凉草地上的根系 AM 真菌群落。我们发现实验诱饵植物根部和周围土壤的 AM 真菌群落结构存在类似的光依赖性变化。然而，在阴凉不耐阴植物的根部，从周围土壤向较低 AM 真菌β多样性的偏差表明，在真菌可利用的植物同化碳有限的条件下，碳优先分配给特定的 AM 真菌。