Characterizing foliar trait variation in sun and shade leaves can provide insights into inter- and intra-species resource use strategies and plant response to environmental change. However, datasets with records of multiple foliar traits from the same individual and including shade leaves are sparse, which limits our ability to investigate trait-trait, trait-environment relationships and trait coordination in both sun and shade leaves. We presented a comprehensive dataset of 15 foliar traits from sun and shade leaves sampled with leaf spectroscopy, including 424 individuals of 110 plant species from 19 sites across eastern North America. We investigated trait variation, covariation, scaling relationships with leaf mass, and the effects of environment, canopy position, and taxonomy on trait expression. Generally, sun leaves had higher leaf mass per area, nonstructural carbohydrates and total phenolics, lower mass-based chlorophyll a + b, carotenoids, phosphorus, and potassium, but exhibited species-specific characteristics. Covariation between sun and shade leaf traits, and trait-environment relationships were overall consistent across species. The main dimensions of foliar trait variation in seed plants were revealed including leaf economics traits, photosynthetic pigments, defense, and structural traits. Taxonomy and canopy position collectively explained most of the foliar trait variation. This study highlights the importance of including intra-individual and intra-specific trait variation to improve our understanding of ecosystem functions. Our findings have implications for efficient field sampling, and trait mapping with remote sensing.

中文翻译：

---

使用北美东部的叶子光谱学量化阳光和遮荫叶子的叶性状变异和协变


表征阳光和遮荫叶子的叶性状变化可以深入了解物种间和物种内的资源利用策略以及植物对环境变化的响应。然而，记录同一个体的多个叶性状（包括遮荫叶）的数据集很少，这限制了我们研究阳光和遮荫叶的性状-性状、性状-环境关系以及性状协调的能力。我们提供了一个综合数据集，其中包含通过叶子光谱采样的阳光和遮荫叶子的 15 种叶性状，其中包括来自北美东部 19 个地点的 110 种植物物种的 424 个个体。我们研究了性状变异、协变、与叶量的尺度关系，以及环境、冠层位置和分类对性状表达的影响。一般来说，太阳叶的单位面积叶质量、非结构碳水化合物和总酚含量较高，叶绿素 a + b、类胡萝卜素、磷和钾含量较低，但表现出物种特异性。阳光和遮荫叶性状之间的协变以及性状与环境的关系在不同物种之间总体上是一致的。揭示了种子植物叶片性状变异的主要维度，包括叶片经济性状、光合色素、防御和结构性状。分类学和冠层位置共同解释了大部分叶性状变异。这项研究强调了个体内和特定内性状变异对于提高我们对生态系统功能的理解的重要性。我们的研究结果对有效的现场采样和遥感特征绘图具有重要意义。