• Root anatomy plays important roles in the control of leaf water relations. However, few studies have evaluated whether and how anatomical traits of absorptive roots influence leaf physiology of herbaceous species in a temperate grassland.
• We measured absorptive root anatomical traits and leaf physiological traits of 15 herbaceous species in a temperate steppe and monitored their responses to increased precipitation in a field stimulating experiment.
• Root anatomical and leaf physiological traits differed among monocotyledonous grasses, monocotyledonous liliaceous species and dicotyledonous forbs. The species with higher stele: root diameter, lower root diameter and cortex thickness exhibited higher transpiration rates and stomatal conductance, but lower intrinsic water‐use efficiency. Increased precipitation enhanced transpiration and stomatal conductance of forbs and lilies, but it enhanced photosynthesis in lilies exclusively. The sensitive response of lilies to precipitation may be related to their large root diameter and cortex thickness.
• In summary, we observed distinct differences in anatomical traits of absorptive roots among plant groups in temperate steppes. These differences drove variations in leaf physiological traits and their diverse responses to precipitation change. These findings highlight the important roles of root anatomical traits in driving leaf‐level physiological processes in temperate grasslands.

中文翻译：

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根部解剖特征决定了温带草原叶片水平的生理特性以及对草本物种降水变化的响应。

• 根系解剖在控制叶水关系中起重要作用。然而，很少有研究评估在温带草原吸收性根的解剖特征是否以及如何影响其草本植物的叶片生理。
• 我们在温带草原中测量了15种草类物种的吸收性根部解剖特征和叶片生理特征，并在田间刺激实验中监测了它们对降水增加的响应。
• 单子叶植物，单子叶植物和双子叶植物的根部解剖和叶片生理特性不同。石碑较高的物种：根部直径，较低的根部直径和皮质厚度显示较高的蒸腾速率和气孔导度，但固有的水分利用效率较低。增加的降水量增强了前叉和百合的蒸腾作用和气孔导度，但仅增强了百合的光合作用。百合对降水的敏感反应可能与它们的大根直径和皮层厚度有关。
• 总之，我们观察到温带草原植物群之间吸收性根的解剖学特征存在明显差异。这些差异驱使叶片生理特性发生变化，并对降水变化产生不同的响应。这些发现突出了根部解剖学特征在温带草原驱动叶级生理过程中的重要作用。