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）通过尺度推绎元素比率（如碳[C]、氮[N]与磷[P]），连接了从基因到全球的各级生物学层级，因此可作为揭示植物特定生理过程的有力工具。然而，尽管碳氮磷化学计量关系对初级生产力可能至关重要，但在群落与生态系统尺度上的相关特征仍不明确。
本研究针对中国境内沿3700公里样带分布的9个天然森林生态系统（涵盖从寒温带到热带的森林类型），测定了不同植物器官、凋落物与土壤的碳、氮、磷含量，以探究碳氮磷化学计量特征及其主要影响因子。我们分别评估了森林生态系统各组分（植物群落、土壤、凋落物与整体生态系统）的碳氮磷化学计量关系，并在群落尺度上分析了803种植物不同器官（叶、枝、干、根）的相关指标。
C:P与N:P比率随纬度升高而降低，其空间格局主要受气候调控。值得注意的是，氮、磷及N:P的内稳性在叶片中最高，其次为枝、根与树干，这支持了“代谢更活跃的器官维持元素含量与比率相对稳定的能力更强”的假说。在群落尺度上，叶片N:P比率表明中国低纬度（即更偏南部）森林受到的磷限制愈发严重。
本研究揭示了碳氮磷化学计量的空间分布格局以及植物群落内不同器官间的元素分配策略，为优化未来生态模型的参数化工作提供了关键的碳氮磷相关数据。