Effects of physiological integration on water use patterns and adaptation strategies in typical alpine wetland clonal plants Potentilla anserina

Understanding plant water uptakes in alpine wetlands are pivotal for sustaining water conservation and maintaining ecological safety of the lower reaches under continuous wetland degradation. However, the physiological integration, a unique process in clonal plants, of water uptake and morphological adaptation in these ecosystems remain insufficiently characterized. In this study, the water uptake sources, functional traits, and biomass allocation of Potentilla anserina were examined along a riverbank distance gradient in the Zoige Alpine Wetland under spacer-severing and intact-spacer treatments. The results indicated that P. anserina predominantly utilized shallow soil water according to the isotope indicators, while the water-source use exhibited pronounced seasonal plasticity, with the strongest sensitivity to soil moisture in autumn when root gradients were well developed. The xylem water isotope values were significantly lower in intact ramets than in severed ones, and the physiological integration significantly promoted the deep-water uptake through clonal networks. Compared with the intact groups, the severed ramets displayed lower specific leaf area (SLA) and leaf water content (LWC), but higher leaf dry matter content (LDMC), water-use efficiency (WUE), sensitivity of water uptake to soil moisture, and greater biomass allocation to belowground organs. These trait adjustments indicate a shift from an acquisitive strategy to a conservative strategy along the leaf economic spectrum. However, root traits did not fully correspond to the leaf economic spectrum, suggesting a multidimensional nature of root function. Overall, these findings emphasize the unignorable impacts of spacers in plant water acquisition and ecological adaptation, providing novel insights into vegetation restoration and water management in alpine wetlands.