Zhou Meng, Bai Wenming, Li Qingmei, Guo Yumeng, Zhang Wen-Hao
State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, China.
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China.
New Phytol. 2021 Feb;229(3):1481-1491. doi: 10.1111/nph.16797. Epub 2020 Aug 10.
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.
根系解剖结构在控制叶片水分关系方面发挥着重要作用。然而，很少有研究评估吸收根的解剖特征是否以及如何影响温带草原草本植物的叶片生理。我们测量了温带草原上15种草本植物的吸收根解剖特征和叶片生理特征，并在田间模拟实验中监测了它们对降水增加的响应。单子叶禾本科植物、单子叶百合科植物和双子叶杂类草的根解剖特征和叶片生理特征存在差异。中柱与根直径比值较高、根直径和皮层厚度较低的物种表现出较高的蒸腾速率和气孔导度，但内在水分利用效率较低。降水增加提高了杂类草和百合的蒸腾作用和气孔导度，但仅提高了百合的光合作用。百合对降水的敏感反应可能与其较大的根直径和皮层厚度有关。总之，我们观察到温带草原植物群中吸收根的解剖特征存在明显差异。这些差异导致了叶片生理特征的变化及其对降水变化的不同响应。这些发现突出了根解剖特征在驱动温带草原叶片水平生理过程中的重要作用。
