Plant life forms shape phosphorus dynamics and rhizosphere microbial communities under gradient nutrient loadings

Phosphorus (P) cycling at the sediment-water interface is a critical driver of eutrophication, yet the roles of aquatic macrophytes of different life forms and their associated rhizosphere microbial communities remain poorly understood. Here, we established three aquatic macrophyte-water-sediment mesocosms involving the submerged Vallisneria natans , rooted floating-leaf Nymphoides peltata , and emergent Typha angustifolia under gradient nutrient loadings to examine the mobility of phosphorus in aquatic macrophyte-water-sediment systems. Results showed life form-specific and phenology-dependent patterns in biomass accumulation, P uptake, P diffusion fluxes, and sediment P fractions. V. natans exhibited a hump-shaped biomass and P uptake trajectory, and effectively suppressed P release from pore water with higher microbial diversity under high nutrient loading. N. peltata exhibits a more conservative strategy, enhancing phosphorus retention within sediments while exerting limited control over sediment-water phosphorus exchange. T. angustifolia consistently sequestered P through extensive belowground organs, with maximal uptake under medium nutrient loading. Compared with the simpler and less stable network of V. natans , T. angustifolia supported a more complex and resilient rhizosphere microbial network. Microbial key taxa showed the close correlations with phosphorus properties of macrophyte-water-sediment systems. These findings emphasize the importance of integrating plant functional traits, phenology, and microbial feedbacks to explain P cycling in wetlands, offering mechanistic insights for optimizing plant-based strategies in eutrophication control and ecological restoration. • Plant life forms and phenology jointly drived phosphorus dynamics. • Rhizosphere microbes emerged as responsive modulators. • Microbial network structure differed significantly among plant life forms. • Microbial diversity and key taxa played crucial roles in mediating P cycling.