Background and aims

In humid regions, the transpiration rate is determined by transpiration demand because of the sufficiently moist soil. However, inhibition of plant water uptake capacity due to soil waterlogging can significantly constrain the transpiration rate even after drainage. This study aimed to evaluate plant hydraulic conductance during soil waterlogging and subsequent reoxygenation and its impact on whole plant transpiration.

Methods

Two experiments were conducted to assess the ecophysiological responses of soybeans during waterlogging (Experiment 1) and reoxygenation (Experiment 2). Transpiration rate, stomatal conductance, leaf water potential, and leaf area were measured. In addition, plant hydraulic conductance was calculated using the root water uptake equation. A simple transpiration model incorporating the response of plant hydraulic conductance to waterlogging was used to evaluate the impact of waterlogging on transpiration estimation.

Results

Waterlogging for more than 3 days reduced plant hydraulic conductance, which persisted even during the post-waterlogging reoxygenation period. Furthermore, leaf water potential, stomatal conductance, and transpiration rate in waterlogging treatment exhibited a lower value than those in control during both waterlogging and reoxygenation. The constructed model effectively reproduced the responses of plant hydraulic conductance and transpiration rate, especially during reoxygenation.

Conclusion

Soil waterlogging significantly reduce the hydraulic conductance of soybean plants, resulting in leaf water stress and depression of transpiration, even during reoxygenation. Our results highlight the importance of integrating plant hydraulic responses with water dynamics models in the soil-plant-atmosphere system.

中文翻译：

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由于土壤涝渍引起的植物水力导率降低，即使在涝涝后再氧合期间，也会抑制甘氨酸 max 的蒸腾速率

 背景和目标

在潮湿地区，由于土壤足够湿润，蒸腾速率由蒸腾需求决定。然而，由于土壤涝渍而抑制植物的水分吸收能力，即使在排水后也会显着限制蒸腾速率。本研究旨在评估土壤涝渍和随后的再氧过程中植物水力导率及其对全株蒸腾的影响。

 方法

进行了两个实验来评估大豆在淹水（实验 1）和复氧（实验 2）期间的生理生态反应。测量蒸腾速率、气孔导度、叶水势和叶面积。此外，使用根系水分吸收方程计算植物水力导率。使用一个简单的蒸腾模型，其中包含植物水力导率对内涝的响应，以评估内涝对蒸腾估计的影响。

 结果

涝渍超过 3 天降低了植物的水力传导，即使在涝渍后再氧合期间也持续存在。此外，在淹水处理中，叶片水势、气孔导度和蒸腾速率均低于涝渍和复氧处理期间的控制值。构建的模型有效地再现了植物水力导流和蒸腾速率的响应，尤其是在复氧过程中。

 结论

土壤涝涝显著降低了大豆植株的水力传导率，导致叶片水分胁迫和蒸腾作用抑制，即使在再氧化过程中也是如此。我们的结果强调了在土壤-植物-大气系统中将植物水力响应与水动力学模型相结合的重要性。