The interactive effects of arbuscular mycorrhizal fungi and nutrient heterogeneity on root foraging behavior and competitive ability of the invasive plant Bidens Pilosa

Root foraging associated with arbuscular mycorrhizal fungi (AMF) play an important role in nutrient uptake. While distribution of nutrients can influence the role of AMF, but the interactive effects of nutrient heterogeneity and AMF on root foraging and plant competition are still unclear. An invasive plant Bidens pilosa and its co-occurring native plant Emilia sonchifolia of the same family Asteraceae were selected. We conducted a common garden experiment of three factors (heterogeneity, AMF and competition). Our results showed that heterogeneity promoted the growth of B. pilosa more than that of E. sonchifolia, while it induced a negative effect of AMF on the growth of B. pilosa under monoculture. AMF exerted negative effects on the growth and nutrient uptake of B. pilosa (only in heterogeneous condition) and E. sonchifolia in monoculture. AMF cheated B. pilosa in decreasing foraging scale while cheated E. sonchifolia in decreasing foraging precision. However, the inter-competition alleviated the negative effects of AMF, and AMF provided stronger tolerance RII rather than suppressive advantage of B. pilosa under heterogeneous condition. Our results highlight the interactive effects of heterogeneity and AMF on root foraging traits and the competition between the invasive species B. pilosa and native species E. sonchifolia.