ABSTRACT

Plant-associated fungi have elementary roles in ecosystem productivity. There is little information on the interactions between arbuscular mycorrhizal (AM) fungal symbiosis, fine endophytic (FE) and dark septate endophytic (DSE) fungi, and their host plants in cold climate systems. In particular, the environmental filters potentially driving the relative abundance of these root symbionts remain unknown. We investigated the interlinkage of plant and belowground fungal responses to simulated herbivory (clipping, fertilization, and trampling) in a subarctic meadow system. AM and FE frequency in the two target plant roots, Potentilla crantzii and Saussurea alpina, was unaffected by simulated herbivory, highlighting the importance and resilience of arbuscule forming mycorrhizas in a range of environmental conditions. Fertilization and trampling increased DSE colonization in P. crantzii roots although generally P. crantzii performance was reduced in these plots. The idiosyncratic responses by DSE fungal frequency in the two host plants in our experiment indicate that the host plant identity has a pivotal role in the DSE fungus–plant outcome. DSE fungal frequency did not respond to environmental manipulations in a manner similar to arbuscular mycorrhizas, suggesting that they have a different role in plant ecology.

摘要

植物相关真菌在生态系统生产力中具有基本作用。在寒冷气候系统中，关于丛枝菌根（AM）真菌共生，细内生（FE）和深色隔生内生（DSE）真菌与其寄主植物之间相互作用的信息很少。特别地，潜在地驱动这些根共生体的相对丰度的环境过滤器仍然是未知的。我们研究了北极草地系统中植物和地下真菌对模拟食草动物（剪草，施肥和践踏）的相互联系。两个目标植物根（委陵菜和雪莲）的AM和FE频率，不受模拟草食动物的影响，突出了在各种环境条件下形成菌根的丛枝的重要性和韧性。施肥和践踏增加了C. p。crantzii根中DSE的定殖，尽管在这些田地中，p。crantzii的表现通常会降低。在我们的实验中，两种寄主植物中DSE真菌频率的特异反应表明，寄主植物的身份在DSE真菌-植物的结局中具有关键作用。DSE真菌频率没有以类似于丛枝菌根的方式对环境操作产生反应，表明它们在植物生态学中的作用不同。