Patterns and drivers of plant C:N:P stoichiometry across a 3000 km aridity gradient

Leaf element stoichiometry plays a crucial role in understanding nutrient dynamics and carbon cycling within ecosystems. However, the biogeographical patterns and driving factors influencing the content and stoichiometric relationships of leaf carbon (C), nitrogen (N), and phosphorus (P) across aridity gradients remain unclear. This study investigated leaf C:N:P stoichiometry along a 3,000 km aridity gradient in China, sampling 36 sites representing forests, grasslands, and deserts. Additionally, the relationships between leaf biochemical traits and environmental factors were explored. Results indicated mean leaf contents of C, N, and P at 588.29 ± 6.9, 19.11 ± 0.3, and 1.33 ± 0.03 g kg-1, respectively. The C:N, C:P, and N:P ratios were obtained as 32.43 ± 0.64, 480.65 ± 11.36, and 15.71 ± 0.4, respectively. The leaf C:N:P stoichiometry exhibited a pervasive nonlinear pattern, and a threshold of approximately 0.7 on an aridity index (AI). Below this threshold (AI 0.7), indicating that P availability increasingly constrained plant growth. Furthermore, plants in arid regions (AI 0.7). These findings provide valuable insights into the spatial distribution of leaf nutrient stoichiometry and offer significant implications for modeling ecosystem nutrient cycles in the context of global warming.