Data from: Different phylogenetic and environmental controls of first-order root morphological and nutrient traits: evidence of multidimensional root traits

1. Although fine roots are essential for the water and nutrient uptake of plants, there is limited understanding of root trait variation and the underlying mechanism.
2. Here, six first-order root morphological and chemical traits were measured for 181 species from eight subtropical and boreal forests to test the hypothesis of different phylogenetic and environmental regulations of root morphological and nutrient traits result in the multidimensions of root traits.
3. Two independent root trait dimensions between root thickness and nutrient traits were detected at both species and community levels. At the species level, diameter-related traits were mainly restricted by phylogenetic structure and showed little plasticity to the changing environments, whereas the variation in woody root nutrient was influenced significantly by soil variables. For community-level traits, the diameter-related axis scores of principal component analysis (PCA) were mainly driven by mean annual temperature (MAT) through shifting species composition, whereas the root nutrient-related axis scores were strongly influenced by soil P availability.
4. From both species and community levels, our study confirms, that the root-thickness-related dimension and root nutrient dimension represent new support for the multidimensionality of root traits which are driven by different selection pressure. This study also underlines that the community-aggregated traits might serve as a promising avenue to improve our understanding of community assemblage processes, allowing us to predict changes of vegetation distributions in a changing climate.

1. 尽管细根（fine roots）对植物获取水分与养分至关重要，但学界对根系功能性状的变异及其内在调控机制的认知仍较为有限。
2. 本研究针对8个亚热带与寒带森林中的181个物种，测定了6个一级根（first-order root）的形态与化学性状，旨在验证"根系形态与养分性状受不同系统发育（phylogenetic）和环境因子调控，进而导致根系功能性状呈现多维度特征"这一假说。
3. 研究在物种与群落两个层面均检测到了两个独立的根系功能性状维度，分别对应根系厚度相关性状与养分相关性状。在物种层面，与直径相关的性状主要受系统发育结构制约，对环境变化的可塑性较弱；而木本根养分的变异则显著受土壤变量的影响。对于群落水平性状而言，主成分分析（principal component analysis, PCA）得到的直径相关轴得分主要通过改变物种组成受年平均温度（mean annual temperature, MAT）驱动，而根系养分相关轴得分则强烈受土壤有效磷（P）可用性的调控。
4. 本研究从物种与群落两个层面证实，根系厚度相关维度与根系养分维度为"受不同选择压力驱动的根系功能性状多维度性"提供了新的支撑证据。本研究同时强调，群落聚集性状或许是加深我们对群落组装过程认知的极具潜力的途径，能够帮助我们预测气候变化背景下植被分布的变化。