Submerged macrophytes promote nutrient use efficiency and growth by enhancing plant trait network connectivity with...

Submerged macrophytes serve as crucial primary producers in freshwater ecosystems, with their growth strategies shaped by environmental factors. Plant trait networks (PTNs) reveal complex trait associations, offering deeper insights into environmental adaptation than traditional methods. However, plant responses to sediment nutrients within the PTN framework remain unclear. This study cultivated 12 common submerged macrophyte species across 11 sediment nutrient gradients for 3 months, measuring 30 functional traits per species. Results show that increasing sediment nutrients enhance PTN connectivity. Specifically, network edges and graph density increase while average path length decreases, indicating greater trait coordination under nutrient-sufficient conditions. Co-occurrence network analysis identifies the N:P ratio as a hub trait strongly linked to others across sediment nutrient gradients. Network connectivity positively correlates with relative growth rate (RGR), and partial least squares structural equation modeling (PLS-SEM) reveals that enhanced connectivity directly improves nutrient use efficiency, subsequently boosting RGR. These findings demonstrate that high trait connectivity facilitates efficient resource acquisition. By exploring adaptive strategies from the PTN perspective, this study uncovers plant adaptation mechanisms under varying nutrient conditions, enhancing understanding of environmental responses and providing a scientific basis for ecological conservation.