Summary Floral traits, including floral display and nutritional rewards from pollen and nectar, drive pollinator visitation. Even within a single plant species, environmental factors can influence the quality and quantity of floral resources. Yet, the ecological interactions driving this variation in floral resources, especially those belowground, remain unknown. Here, we investigate how soil microbial community composition and nutrient availability, specifically distinct arbuscular mycorrhizal fungi (AMF) species and phosphorus (P) supply, affect plant growth, AMF traits, floral traits, and how that, in turn, affects bee visitation. We found that increased AMF richness of functional diversity enhanced floral display (flower size and number) and rewards (nectar volume and pollen protein) and increased bee visitation. Using structural equation modeling, we found that AMF associations could boost bee visitation by enhancing flower size. However, trade‐offs occur; flower size correlates negatively with root colonization but positively with hyphal length, suggesting that AMF traits drive the effects of AMF on flower growth. Overall, the effect of AMF on floral traits and bee visitation was not homogenous; instead, AMF trait differences interact with P supply, resulting in varying effects on floral traits and subsequently bee foraging dynamics. These results highlight that focusing on beneficial belowground interactions could provide an opportunity to bolster bee visitation.

中文翻译：

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丛枝菌根相互作用和营养供应介导花性状变异和传粉媒介访问


总结 花卉特性，包括花卉展示和花粉和花蜜的营养奖励，推动了传粉媒介的访问。即使在单一植物物种中，环境因素也会影响花卉资源的质量和数量。然而，驱动花卉资源（尤其是地下花卉资源）这种变化的生态相互作用仍然未知。在这里，我们研究了土壤微生物群落组成和养分可用性，特别是不同的丛枝菌根真菌 （AMF） 物种和磷 （P） 供应，如何影响植物生长、AMF 性状、花性状，以及这反过来又如何影响蜜蜂的访问。我们发现，功能多样性的 AMF 丰富度增加，增强了花的展示（花的大小和数量）和奖励（花蜜量和花粉蛋白），并增加了蜜蜂的访问量。使用结构方程建模，我们发现 AMF 关联可以通过增加花的大小来促进蜜蜂的访问。但是，需要权衡取舍;花的大小与根定植呈负相关，但与菌丝长度呈正相关，表明 AMF 性状驱动 AMF 对花生长的影响。总体而言，AMF 对花性状和蜜蜂访问量的影响并不均匀;相反，AMF 性状差异与 P 供应相互作用，导致对花性状和随后的蜜蜂觅食动力学产生不同的影响。这些结果强调，专注于有益的地下互动可以提供促进蜜蜂访问的机会。