Table 1_Impact of phosphorus supply and arbuscular mycorrhizal fungi inoculation on rhizosphere fungal communities and growth of Macadamia integrifolia seedlings.xlsx

IntroductionPhosphorus (P) limitation constrains the growth of Macadamia integrifolia in subtropical soils, despite intrinsic adaptations such as cluster roots and rhizosphere P mobilization. However, the role of arbuscular mycorrhizal fungi (AMF) in enhancing P acquisition under varying P availability and inoculum identity remains unclear.
MethodsWe conducted a controlled pot experiment with three P levels (P0, P1, P2) and two AMF treatments (indigenous consortium and Glomus mosseae), assessing seedling growth, biomass allocation, organ-level P concentrations, rhizosphere soil properties, and fungal community composition.
ResultsSeedling growth and biomass allocation responded non-linearly to P, with maximal aboveground biomass at P1. Notably, G. mosseae inoculation under P1 increased aboveground biomass by 42.9% and root P concentration by 18.4%, whereas the indigenous AMF consortium enhanced leaf P and rhizosphere P under low-P conditions. AMF colonization was strongly associated with total plant biomass but decoupled from short-term P uptake efficiency. Rhizosphere fungal α-diversity and community composition varied with P supply and AMF identity, with Glomeromycota enrichment and reduced saprotroph abundance in inoculated treatments.
DiscussionThese findings demonstrate context-dependent AMF effects that integrate strain-specific functional traits with intrinsic plant P-acquisition strategies, highlighting functional differentiation between growth promotion and immediate nutrient acquisition. This study provides quantitative guidance for optimizing growth and P-use efficiency in low-P-adapted woody crops.