Data from: C:N:P stoichiometry in China's forests: from organs to ecosystems

Ecological stoichiometry connects different levels of biology, from the gene to the globe, by scaling up elemental ratios (e.g., carbon [C], nitrogen [N], and phosphorus [P]). Thus, ecological stoichiometry could be a powerful tool for revealing certain physiological processes of plants. However, C:N:P stoichiometry remains unclear at the community and ecosystem level, despite it being potentially important for primary productivity. In this study, we measured the C, N, and P content of different plant organs, litter, and soil in 9 natural forest ecosystems (cold-temperate to tropical forests along a 3700-km transect in China) to explore C:N:P stoichiometry and the main influencing factors. C:N:P stoichiometry was evaluated for different components in the forest ecosystems (plant community, soil, litter, and ecosystem) and, at the community level, for different organs (leaves, branches, trunks, and roots) from 803 plant species. The ratios of C:P and N:P decreased with increasing latitude, with spatial patterns being primarily regulated by climate. Interestingly, the homeostasis of N, P, and N:P was highest in leaves, followed by branches, roots, and trunk, supporting the hypothesis that more active organs have a higher capacity to maintain relatively stable element content and ratios. At the community level, the leaf N:P ratio indicated increasing P limitation in forests of lower latitude (i.e., more southerly) in China's forests. Our findings demonstrate the spatial patterns of C:N:P stoichiometry and the strategies of element distribution among different organs in a plant community, providing important data on C:N:P to improve the parameterization of future ecological models.生态化学计量学（ecological stoichiometry）通过尺度上推元素比值（如碳[C]、氮[N]与磷[P]），连接了从基因到全球尺度的各级生物学层级。因此，生态化学计量学可作为揭示植物特定生理过程的有力工具。然而，尽管C:N:P化学计量特征对生态系统初级生产力可能具有重要意义，但群落与生态系统尺度下的该特征仍不明确。 本研究针对中国境内沿3700公里样带分布的9处天然森林生态系统（涵盖寒温带至热带森林），测定了不同植物器官、枯落物及土壤的碳、氮、磷含量，以探究C:N:P化学计量特征及其主要影响因子。本研究分别评估了森林生态系统各组分（植物群落、土壤、枯落物及整体生态系统）的C:N:P化学计量特征，并在群落尺度下分析了803种植物的不同器官（叶、枝、干、根）的化学计量特征。 研究结果显示，C:P与N:P比值随纬度升高而降低，其空间分布格局主要受气候调控。有趣的是，氮、磷及N:P的内稳态（homeostasis）在叶片中最高，依次为枝、根与树干，这一发现支持“代谢更活跃的器官维持元素含量与比例稳定的能力更强”的假说。在群落尺度下，叶片N:P比值表明中国低纬度（即更偏南部）的森林受到的磷限制程度更高。 本研究阐明了C:N:P化学计量特征的空间分布格局以及植物群落内不同器官的元素分配策略，可为优化未来生态模型的参数化提供关键的C:N:P计量数据。