Japan Science and Technology Agency, PRESTO, Kawaguchi, Saitama, 332-0012, Japan.
Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, 113-8657, Japan.
New Phytol. 2021 Mar;229(6):3133-3140. doi: 10.1111/nph.17093. Epub 2020 Dec 20.
Drought and flooding are contrasting abiotic stressors for plants. Evidence is accumulating for root anatomical traits being essential for the adaptation to drought or flooding. However, an integrated approach to comprehensively understand root anatomical traits has not yet been established. Here we analysed the root anatomical traits of 18 wild Poaceae species differing in adaptation to a range of soil water content. Regression model analyses revealed the optimal anatomical traits that were required by the plants to adapt to low or high soil water content. While the area and number of each root tissue (e.g. stele, cortex, xylem or aerenchyma) were not strongly correlated to the soil water content, the ratio of the root tissue areas (cortex to stele ratio (CSR), xylem to stele ratio (XSR) and aerenchyma to cortex ratio (ACR)) could fully explain the adaptations of the wild Poaceae species to the soil water gradients. Our results demonstrate that the optimal anatomical traits for the adaptations to soil water content can be determined by three indices (i.e. CSR, XSR and ACR), and thus we propose that these root anatomical indices can be used to improve the tolerance of crops to drought and flooding stresses.
干旱和洪涝是植物面临的两种截然相反的非生物胁迫。有证据表明，根系解剖结构特征对于植物适应干旱或洪涝胁迫至关重要。然而，目前还没有建立一种综合的方法来全面了解根系解剖结构特征。在这里，我们分析了 18 种野生禾本科植物的根系解剖结构特征，这些植物在适应不同土壤含水量方面存在差异。回归模型分析揭示了植物适应低或高土壤含水量所需的最佳解剖结构特征。虽然每个根系组织（例如中柱、皮层、木质部或通气组织）的面积和数量与土壤含水量没有很强的相关性，但根系组织面积的比例（皮层与中柱比（CSR）、木质部与中柱比（XSR）和通气组织与皮层比（ACR））可以完全解释野生禾本科植物对土壤水分梯度的适应。我们的结果表明，适应土壤含水量的最佳解剖结构特征可以通过三个指数（即 CSR、XSR 和 ACR）来确定，因此我们提出这些根系解剖学指数可用于提高作物对干旱和洪涝胁迫的耐受性。
