Differential adaptative strategies to phosphorus limitation in tropical rainforests dominated by trees associated with arbuscular and ectomycorrhizal fungi

Tropical rainforests on low-phosphorus (P) soils are highly biodiverse and productive, playing a crucial role in climate change mitigation. However, the adaptation mechanisms of tropical rainforest dominated by trees associated with different mycorrhizal symbioses (arbuscular mycorrhizal (AM) and ectomycorrhizal fungi (ECM)) to P-deficient environments remain unclear. Through a 10-year field experiments with nitrogen (N) and P additions in AM- and ECM-dominated stands, we first investigated leaf nutrient content and resorption efficiencies of eight species in each stand. We further explored how litter, soil, and microbes maintain P supply to plants. We found that both AM- and ECM-dominated forests are P-limited. AM-dominated forest exhibited higher soil phoD gene abundance and fungal diversity, while ECM-dominated forest displayed higher soil phosphatase activity. Regression and random forest analyses revealed that AM-dominated forest employ diverse P-acquisition strategies, including increased foliar P resorption efficiency, soil phosphatase activity, and fungal diversity. In contrast, ECM-dominated forest preferred to enhance soil phosphatases activity and mineralize moderately liable P, thereby alleviating P limitation. These findings show joint influence of litter, soil, and microorganisms on plant P acquisition, and P-regulated processes vary by mycorrhizal types. Our study enhances understanding of the effects of global change on biogeochemical processes in tropical rainforests.