Álvarez-Maldini Carolina, Acevedo Manuel, Estay Daniela, Aros Fabián, Dumroese R Kasten, Sandoval Simón, Pinto Manuel
Instituto Ciencias Agroalimentarias Animales y Ambientales (ICA3), Campus Colchagua, Universidad de O'Higgins, San Fernando, Chile.
Centro Tecnológico de la Planta Forestal, Instituto Forestal, Sede Biobío, San Pedro de la Paz, Chile.
Front Plant Sci. 2022 Aug 25;13:974050. doi: 10.3389/fpls.2022.974050. eCollection 2022.
The search for drought tolerant species or cultivars is important to address water scarcity caused by climate change in Mediterranean regions. The anisohydric-isohydric behavior concept has been widely used to describe stomatal regulation during drought, simply in terms of variation of minimal water potential (Ψ) in relation to pre-dawn water potential (Ψ). However, its simplicity has sometimes failed to deliver consistent results in describing a complex behavior that results from the coordination of several plant functional traits. While (almond) is known as a drought tolerant species, little information is available regarding consistent metrics to discriminate among cultivars or the mechanisms underlying drought tolerance in almond. Here we show a sequence of plant stomatal, hydraulic, and wilting responses to drought in almonds, and the main differences between anisohydric and isohydric cultivars. In a pot desiccation experiment we observed that stomatal closure in is not driven by loss in turgor or onset of xylem cavitation, but instead, occurs early in response to decreasing Ψ that could be related to the protection of the integrity of the hydraulic system, independently of cultivar. Also, we report that anisohydric cultivars of are characterized by maximum stomatal conductance, lower water potentials for stomatal closure and turgor loss, and lower vulnerability to xylem cavitation, which are traits that correlated with metrics to discriminate anisohydric and isohydric behavior. Our results demonstrate that presents a strategy to avoid cavitation by closing stomata during the early stages of drought. Future research should also focus on below-ground hydraulic traits, which could trigger stomatal closure in almond.
寻找耐旱物种或品种对于应对地中海地区气候变化导致的水资源短缺至关重要。等水线-非等水线行为概念已被广泛用于描述干旱期间的气孔调节，简单来说就是根据最小水势（Ψ）相对于黎明前水势（Ψ）的变化来描述。然而，其简单性有时未能在描述由多种植物功能性状协调产生的复杂行为时给出一致的结果。虽然扁桃被认为是一种耐旱物种，但关于区分不同品种的一致指标或扁桃耐旱机制的信息却很少。在这里，我们展示了扁桃对干旱的一系列植物气孔、水力和萎蔫反应，以及非等水线和等水线品种之间的主要差异。在盆栽干燥实验中，我们观察到扁桃的气孔关闭不是由膨压丧失或木质部空化的开始驱动的，而是相反，在响应可能与保护水力系统完整性相关的Ψ降低时早期发生，与品种无关。此外，我们报告说，扁桃的非等水线品种的特征是最大气孔导度、较低的气孔关闭和膨压丧失水势，以及较低的木质部空化脆弱性，这些特征与区分非等水线和等水线行为的指标相关。我们的结果表明，扁桃呈现出一种在干旱早期通过关闭气孔来避免空化的策略。未来的研究还应关注地下水力性状，其可能触发扁桃的气孔关闭。
