Arbuscular mycorrhiza increases the facilitation between adult plant and seedling but root‐knot nematode inhibits it

Abstract

Soil biotic and abiotic factors can affect the interaction between invasive and native species. However, it is not yet clear how arbuscular mycorrhizal (AM) symbiosis affects the interaction between adult invasive plants and neighboring seedlings. We used an invasive weed (Bidens frondosa) to test the hypothesis that adult invasive plants facilitate the growth of neighboring seedlings through AM symbiosis, and this facilitation can be inhibited by the biological stress of root‐knot nematode infection. The results showed that the height and total biomass of seedlings near the adult plant increased, indicating that the belowground effects mediated by AM symbiosis played a facilitative role. The positive growth response to resource allocation between adult plant and neighboring seedlings through mycorrhizal connection was inhibited when adult plants were infected by root‐knot nematode. Only the total biomass and root–shoot ratio of adult plants were increased, while seedling growth performance did not change. Our results supported the hypothesis that adult invasive plants can facilitate their neighboring seedlings growth through AM symbiosis and the benefits vary with biotic stress on adult plant. These findings provided important evidence to explain the role of AM symbiosis in plant invasion.