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. 尽管细根是植物水分与养分吸收的核心器官，但学界对根性状变异及其潜在调控机制的认知仍较为匮乏。 2. 本研究针对8个亚热带与寒温带森林的181个物种，测定了6项一级根（first-order root）的形态与化学性状，旨在验证“根形态性状与养分性状受不同系统发育和环境调控，进而催生根性状多维性”这一假说。 3. 研究在物种和群落两个水平上，均检测到根直径（root thickness）相关性状与养分性状分属两个独立的根性状维度。在物种水平上，直径相关性状主要受系统发育结构限制，对环境变化的表型可塑性极低；而木质根养分（woody root nutrient）的变异则显著受土壤变量调控。在群落水平上，主成分分析（PCA）得到的直径相关轴得分主要由年平均温度（MAT）通过改变物种组成驱动，而根养分相关轴得分则强烈受土壤磷有效性的影响。 4. 本研究从物种与群落两个层面证实，根直径相关维度与根养分维度为根性状的多维性提供了新的实证支持，而二者的驱动机制为不同的选择压力。此外，本研究还强调，群落聚集性状（community-aggregated traits）有望成为解析群落组装过程的有效途径，助力我们预测气候变化背景下植被分布的动态变化。