Interactions between arbuscular mycorrhizal fungi and soil properties jointly influence plant C, N, and P stoichiometry in West Lake, Hangzhou

Arbuscular mycorrhizal fungi (AMF) play important roles in terrestrial plants via mutualistic symbiosis. However, knowledge about the functions of AMF in aquatic plants remains limited. Here, four dominate emergent plant communities in West Lake, Hangzhou were chosen, the characteristics of AMF, plant C, N, and P stoichiometry, and soil properties were investigated. The results showed that both AMF infection rates and the number of AMF spore species increased, suggesting a great mutualism between AMF and emergent plants. Contents of C, N, and P in aboveground biomass and roots and their ratios varied greatly among these four emergent plants. Moreover, AMF infection frequency showed a significant negative correlation with aboveground biomass N (p < 0.05), whereas the rates of arbuscular mycorrhiza formation and vesicular formation after root infection showed significant negative correlations with root N and root N/P. Soil total C, soil total N, soil total P, and oxidation–reduction potential (ORP) were significantly associated with AMF infection characteristics. Our main findings are that the results of redundancy analysis and path analysis further indicated that soil C, N, and P contents, and ORP affected plant C, N, and P contents and their stoichiometry directly. Meanwhile, soil properties can also regulate plant ecological stoichiometry indirectly via altering AMF mycorrhiza. Our findings highlight that interactions between AMF and soil play crucial roles in regulating plant ecological stoichiometry and can be treated as a whole in investigating the relationships between plant and soil.