欧亚国际

来自国外的科学家利用Plantarray植物逆境研究系统在知名期刊Journal of Experimental Botany上发表了题为Modify Root/Shoot ratio Alleviate Root Water Influxes in Wheat under Drought Stress的文章。

植物所经历的干旱强度取决于土壤水分状况和大气变量，如温度、辐射和空气蒸汽压差（VPD）。虽然这些土壤和大气因素在地上部结构中的作用已经得到了很好的描述，但地上部和根系作为一个连续统一的动态相互作用在多大程度上受基因型变异的控制尚不清楚。在这里，我们利用野生二聚体导入系（IL20）对这些相互作用进行了定位，该系具有明显的干旱诱导的茎根比变化及其干旱敏感的轮回亲本Svevo。利用蒸渗分析平台，我们发现IL20在干旱胁迫下保持了较高的根系水分流入和气体交换，从而支持了更好的生长。有趣的是，在较低的VPD下，IL20在根系水分流入和蒸腾方面的优势在日循环中表现得更早，因此支持较高的蒸腾效率。结构方程模型的应用表明，在干旱条件下，VPD和辐射对蒸腾速率具有拮抗作用，而根系水分流入对叶片的高大气压响应起反馈作用。总之，我们的结果表明，干旱引起的根冠比变化可以在由水分和大气参数确定的较短时间窗口内提高植物的吸水潜力。

缩写：同化率（A）、干旱胁迫（DS）、干重（DW）、渗入线（IL）、归一化蒸腾速率（E）、气孔导度（gs）、结构方程模型（SEM）、蒸气压亏缺（VPD）、水分利用效率（WUE）、充分灌溉（WW）、全冠层导度（gsc）

Modify Root/Shoot ratio Alleviate Root Water Influxes in Wheat under Drought Stress

Harel Bacher, Yoav Sharaby, Harkamal Walia, Zvi Peleg

Journal of Experimental Botany, erab500, http://doi.org/10.1093/jxb/erab500

Published:

16 November 2021 

Abstract

Drought intensity as experienced by plants depends upon soil moisture status and atmospheric variables such as temperature, radiation, and air vapour pressure deficit (VPD). Although the role of shoot architecture with these edaphic and atmospheric factors is well-characterized, the extent to which shoot and root dynamic interactions as a continuum are controlled by genotypic variation is less known. Here, we targeted these interactions using a wild emmer introgression line (IL20) with a distinct drought-induced shift in the shoot-to-root ratio and its drought-sensitive recurrent parent Svevo. Using a gravimetric platform, we show that IL20 maintained higher root water influx and gas exchange under drought stress, which supported a greater growth. Interestingly, the advantage of IL20 in root water influx and transpiration was expressed earlier during the daily diurnal cycle under lower VPD and therefore supported higher transpiration efficiency. Application of structural equation model indicates that under drought, VPD and radiation are antagonistic to transpiration rate, whereas the root water influx operates as feedback for the higher atmospheric responsiveness of leaves. Collectively, our results suggest that a drought-induced shift in root-to-shoot ratio can improve plant water uptake potential in a short preferable time window determined by both water and atmospheric parameters.

Abbreviations: Assimilation rate (A), drought stress (DS), dry weight (DW), introgression line (IL), normalized transpiration rate (E), stomatal conductance (gs), structural equation modelling (SEM), vapour pressure deficit (VPD), water-use efficiency (WUE), well-watered (WW), whole canopy conductance (gsc)