Aims and scope

Arbuscular mycorrhizal (AM) fungi form soil hyphal networks that facilitate plant nutrient uptake. AM fungi can be less effective plant-mutualists in cultivated fields because agricultural stressors reduce their functional diversity and may favour a less mutualistic genotype. Previously, we showed restoration of retired cultivated fields stimulated AM fungal species diversity. Here, we tested if restoration also stimulated mutualistic functions of AM fungi.

Methods

Soil inoculum was collected from five farm sites in cultivated fields and adjacent prairies that had been restored 8–12 years previously. Plant-growth promoting functions of AM fungi were quantified under greenhouse conditions by comparing biomass and phosphorus content in Trifolium pratense and Andropogon gerardii plants whose access to AM fungal networks was severed or left intact.

Results

Plant biomass was higher in the intact vs. severed AM fungal network treatment but the mean effect did not differ between restored prairie and cultivated field inoculum. Nonetheless, soil inoculum source effect on biomass depended on site location for T. pratense, but not A. gerardii. Access to AM fungal networks from cultivated fields increased phosphorus in T. pratense, but reduced phosphorus in A. gerardii, compared to restored prairies. Soil inoculum source effects on phosphorus also depended on farm site location.

Conclusions

Ecological restoration did not universally increase mutualistic functions of AM fungi. However, the fact that plant responses to AM fungi were dependent on site location and host identity suggests that ecological restoration has complex effects on the mutualistic benefits that plants receive from AM fungi.

中文翻译：

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生态恢复对丛枝菌根真菌提供的互惠服务的影响取决于地点位置和宿主身份

 目标和范围

丛枝菌根 （AM） 真菌形成土壤菌丝网络，促进植物养分吸收。AM 真菌在耕地中可能不太有效，因为农业压力源降低了它们的功能多样性，并且可能有利于不太共生的基因型。以前，我们展示了退役耕地的恢复刺激了 AM 真菌物种的多样性。在这里，我们测试了恢复是否也刺激了 AM 真菌的共生功能。

 方法

土壤接种物是从 8-12 年前恢复的耕地和邻近草原的 5 个农场地点收集的。通过比较 Trifolium pratense 和 Andropogon gerardii 植物的生物量和磷含量，在温室条件下量化 AM 真菌的植物生长促进功能，这些植物对 AM 真菌网络的访问被切断或保持不变。

 结果

与切断的 AM 真菌网络处理相比，植物生物量更高，但恢复草原和耕地接种物的平均效果没有差异。尽管如此，土壤接种来源对生物量的影响取决于 T. pratense 的地点位置，而不是 A. gerardii。与恢复的草原相比，从耕地进入 AM 真菌网络增加了 T. pratense 的磷，但减少了 A. gerardii 的磷。土壤接种源对磷的影响也取决于农场位置。

 结论

生态恢复并未普遍增加 AM 真菌的共生功能。然而，植物对 AM 真菌的反应取决于地点位置和宿主身份的事实表明，生态恢复对植物从 AM 真菌中获得的互惠利益具有复杂的影响。