Compared to evergreens, deciduous tree species usually have higher photosynthetic efficiency to complete vegetative and reproductive growth in a shorter growing season. However, the nutrient basis for the differentiation of photosynthesis functional traits between evergreen and deciduous tree species has not yet been clarified. Thirty evergreen and twenty deciduous angiosperm tree species from a subtropical common garden were compared in terms of photosynthetic traits and leaf nutrients. Generally, their differences in area-based photosynthetic capacity were uncorrelated with area-based leaf nutrient content but were caused by the fraction of nitrogen allocated to photosynthetic components. By comparison, the differences in mass-based photosynthetic capacity were more correlated with leaf nitrogen content than leaf phosphorus and potassium content. Convergence in phosphorus and potassium constraints to photosynthesis occurred in deciduous tree species but not in evergreen tree species. Furthermore, leaf C/N ratio played a more significant role than leaf mass per area in determining the differentiation of photosynthetic traits between evergreen and deciduous groups. Our findings provide insight into the nutrient basis for photosynthetic carbon gain and functional strategies across trees species.

中文翻译：

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亚热带常绿乔木和落叶乔木光合性状分化的叶片养分基础


与常绿树相比，落叶树种通常具有更高的光合作用效率，可以在较短的生长季节内完成营养和生殖生长。然而，常绿树种和落叶树种之间光合作用功能性状分化的营养基础尚未阐明。对来自亚热带普通花园的 30 种常绿和 20 种落叶被子植物树种的光合特性和叶片养分进行了比较。一般来说，它们基于面积的光合能力的差异与基于面积的叶片养分含量无关，而是由分配给光合成分的氮分数引起的。相比之下，基于质量的光合能力的差异与叶片氮含量的相关性高于叶片磷和钾含量。磷和钾对光合作用的限制收敛发生在落叶树种中，但不发生在常绿树种中。此外，叶片 C/N 比在决定常绿类群和落叶类群之间光合性状分化方面的作用比单位面积叶质量更重要。我们的研究结果为光合碳增益的营养基础和树种的功能策略提供了见解。