Abstract Drought is one of the most important constraints to crop productivity worldwide. Control of plant responses to drought is very complex. The mechanisms and their intensity may differ between species and/or genotypes ultimately conditioning tolerance or susceptibility. We explore here the strategy set up by two oat cultivars to cope with drought based on root morphological, anatomical, physiological and molecular studies. A dramatic and rapid abscisic acid increase in the susceptible genotype resulted in a tight and rapid reduction of stomatal conductance. Despite of this, leaf water potential decreased concomitantly due to a decrease in root hydraulic conductivity. By contrast, the resistant genotype, showed a mild and slow increase in abscisic acid that allowed maintaining transpiration longer. This response was linked to an increase in root hydraulic conductance through an increase in total root length and in the length of the thinnest roots as well as a rise in root conductivity. This was also coupled with anatomical changes leading to a reduction of metabolic cost. These changes allowed the resistant genotype to maintain higher water potential reducing drought symptoms and promoting growth under water deficit conditions.

中文翻译：

---

燕麦的抗旱性涉及 ABA 介导的蒸腾作用和根系导水率调节

摘要 干旱是全球作物生产力最重要的制约因素之一。控制植物对干旱的反应非常复杂。最终调节耐受性或易感性的物种和/或基因型之间的机制及其强度可能不同。我们在此基于根部形态学、解剖学、生理学和分子学研究，探索由两个燕麦品种建立的应对干旱的策略。易感基因型中脱落酸的急剧增加导致气孔导度的急剧下降。尽管如此，由于根部导水率的降低，叶水势也随之降低。相比之下，抗性基因型显示脱落酸的温和缓慢增加，从而使蒸腾作用保持更长时间。这种反应与通过增加根总长度和最细根的长度以及根传导率的增加来增加根系水力传导率有关。这还与导致代谢成本降低的解剖结构变化相结合。这些变化使抗性基因型能够保持较高的水势，从而减少干旱症状并促进缺水条件下的生长。