Contribution of different arbuscular mycorrhizal fungal inoculum to Elymus nutans under nitrogen addition
Arbuscular mycorrhizal (AM) fungi are known to promote plant growth and nutrient uptake, but the role of AM fungi play in nitrogen (N) uptake is still unclear. Therefore, a pot experiment was conducted to assess the effects of N addition (0 and 200 kg N ha−1 yr−1) and AM inoculation (Diversispora eburnea, Claroideoglomus etunicatum, Paraglomus occultum, 1:1:1 mixture of each AM fungal species and a non-mycorrhizal control) on AM root colonization, plant growth, N and P nutrition. Our results showed that AM root colonization was unaffected by N addition, but was significantly affected by different AM fungal species. D. eburnea and C. etunicatum showed a significant higher root colonization than P. occultum. Plant biomass, N and P content was significantly enhanced by N addition when inoculated with D. eburnea and AM mixture, but unaffected by N addition when inoculated with C. etunicatum and P. occultum. On the other hand, inoculation with different AM fungal species resulted in different plant response. For instance, inoculation with D. eburnea and AM mixture contributed substantially to plant biomass, N and P nutrition. Whereas, inoculation with C. etunicatum and P. occultum did not significantly enhance plant biomass, N and P content regardless of N addition. In conclusion, these results indicated that the plant response to N addition depends on AM fungal species, and emphasized that significant functional diversity exists among AM fungal species.