Leaf C:P ratio as a universal indicator of photosynthesis in subtropical woody species: Stoichiometric thresholds and metabolic trade‐offs

作者：Minghao Chen, Yahong Zheng, 蔡敏玲, Songbo Tang, Lingling Zhang, Xianzhen Luo, Xi Zhang, Enqing Hou, yuanwen kuang, Dazhi Wen · 发表于：Functional Ecology · 年份：2026 · DOI：10.1111/1365-2435.70364 · 研究领域：Plant Water Relations and Carbon Dynamics、Plant nutrient uptake and metabolism、Soil Carbon and Nitrogen Dynamics

Abstract The stoichiometric ratios of carbon (C), nitrogen (N) and phosphorus (P) serve as important indicators for assessing nutrient balance in forest ecosystems, but their relationships with photosynthetic dynamics require deeper characterization. This study systematically examined the associations between leaf C‐N‐P stoichiometry and photosynthetic traits across 92 dominant woody species in subtropical regions. We found that the C:P ratio exhibited the greatest variation across species compared to other stoichiometric ratios, indicating that it responds sensitively to environmental conditions. Among all stoichiometric parameters, leaf C:P displayed the strongest correlation with maximum net photosynthetic rate ( A max ), closely linked with its coordinated variations in stomatal conductance, chlorophyll content and specific leaf area. In‐depth metabolic analysis of 31 representative species revealed that leaf C:P ratio effectively captured two critical processes: (1) the accumulation patterns of photosynthetic products and (2) the metabolic P allocation regulated by acid phosphatase activity. This dual sensitivity enabled C:P to serve as a synthetic indicator reflecting both carbon assimilation efficiency and phosphorus metabolic status. In contrast, N:P ratio showed limited predictive value for A max due to its inability to integrate the co‐variation of photosynthetic product dynamics and nutrient regulation. Our findings establish leaf C:P ratio as a robust bioindicator...