Université Clermont Auvergne, INRAE, PIAF, F-63000 Clermont-Ferrand, France.
Institut Technique Interprofessionnel Plantes à Parfum, Médicinal, Aromatiques et Industrielles, 26740 Montboucher-sur-Jabron, France.
J Exp Bot. 2022 Jun 2;73(11):3699-3710. doi: 10.1093/jxb/erac061.
Acoustic emission analysis is promising to investigate the physiological events leading to drought-induced injury and mortality. However, their nature and source are not fully understood, making this technique difficult to use as a direct measure of the loss of xylem hydraulic conductance. Acoustic emissions were recorded during severe dehydration in lavender plants (Lavandula angustifolia) and compared with the dynamics of embolism development and cell damage. The timing and characteristics of acoustic signals from two independent recording systems were compared by principal component analysis (PCA). Changes in water potential, branch diameter, loss of hydraulic conductance, and cellular damage were also measured to quantify drought-induced damages. Two distinct phases of acoustic emissions were observed during dehydration: the first one associated with a rapid loss of diameter and a significant increase in loss of xylem conductance (90%), and the second with slower changes in diameter and a significant increase in cellular damage. Based on PCA, a developed algorithm discriminated hydraulic-related acoustic signals from other sources, proposing a reconstruction of hydraulic vulnerability curves. Cellular damage preceded by hydraulic failure seems to lead to a lack of recovery. The second acoustic phase would allow detection of plant mortality.
声发射分析有望研究导致干旱胁迫伤害和死亡的生理事件。然而，其性质和来源尚未完全了解，这使得该技术难以直接作为木质部水力传导能力丧失的测量指标。本研究在薰衣草（Lavandula angustifolia）严重脱水过程中记录了声发射，并将其与栓塞形成和细胞损伤的动力学进行了比较。通过主成分分析（PCA）比较了两个独立记录系统的声信号的时间和特征。还测量了水势、枝条直径、水力传导损失和细胞损伤的变化，以量化干旱胁迫造成的损伤。在脱水过程中观察到两种截然不同的声发射阶段：第一个阶段与直径的快速损失和木质部导水率的显著增加（90%）相关，第二个阶段与直径的较慢变化和细胞损伤的显著增加相关。基于 PCA，开发的算法可将与水力相关的声信号与其他来源区分开来，提出了水力脆弱性曲线的重建。水力失败前的细胞损伤似乎导致缺乏恢复。第二阶段的声发射可能可以检测到植物的死亡。
