Wilkening Jean V, Dawson Todd E, Thompson Sally E
Civil and Environmental Engineering, University of California, Berkeley, California, USA.
Civil, Environmental, and Geo-Engineering, University of Minnesota, Minneapolis, Minnesota, USA.
Plant Cell Environ. 2025 May;48(5):3673-3690. doi: 10.1111/pce.15349. Epub 2025 Jan 14.
Understanding and predicting plant water dynamics during and after water stress is increasingly important but challenging because the high-dimensional nature of the soil-plant-atmosphere system makes it difficult to identify mechanisms and constrain behaviour. Datasets that capture hydrological, physiological and meteorological variation during changing water availability are relatively rare but offer a potentially valuable resource to constrain plant water dynamics. This study reports on a drydown and re-wetting experiment of potted Populus trichocarpa, which intensively characterised plant water fluxes, water status and water sources. We synthesised the data qualitatively to assess the ability to better identify possible mechanisms and quantitatively, using information theory metrics, to measure the value of different measurements in constraining plant water fluxes and water status. Transpiration rates declined during the drydown and then showed a delayed and partial recovery following rewatering. After rewatering, plant water potentials also became decoupled from transpiration rates and the canopies experienced significant yellowing and leaf loss. Hormonal mechanisms were identified as a likely driver, demonstrating a mechanism with sustained impacts on plant water fluxes in the absence of xylem hydraulic damage. Quantitatively, the constraints offered by different measurements varied with the dynamic of interest, and temporally, with behaviour during recovery more difficult to constrain than during water stress. The study provides a uniquely diverse dataset offering insight into mechanisms of plant water stress response and approaches for studying these responses.
理解和预测水分胁迫期间及之后的植物水分动态变得越来越重要，但也具有挑战性，因为土壤-植物-大气系统的高维性质使得难以确定其机制并限制其行为。能够捕捉不断变化的水分可利用性期间的水文、生理和气象变化的数据集相对较少，但为限制植物水分动态提供了潜在的宝贵资源。本研究报告了盆栽毛果杨的干旱和再湿润实验，该实验详细表征了植物水分通量、水分状况和水源。我们对数据进行了定性综合，以评估更好地识别可能机制的能力，并使用信息论指标进行定量分析，以衡量不同测量在限制植物水分通量和水分状况方面的价值。干旱期间蒸腾速率下降，再浇水后蒸腾速率出现延迟且部分恢复。再浇水后，植物水势也与蒸腾速率解耦，树冠出现明显变黄和落叶现象。激素机制被确定为可能的驱动因素，这表明在没有木质部水力损伤的情况下，存在一种对植物水分通量有持续影响的机制。从定量角度来看，不同测量提供的限制随感兴趣的动态变化而变化，从时间角度来看，恢复期间的行为比水分胁迫期间更难限制。该研究提供了一个独特的多样化数据集，有助于深入了解植物水分胁迫响应机制以及研究这些响应的方法。
