干旱胁迫植物个体生理响应及其生态模型预测研究进展

全球气候突变导致干旱事件频发，进而易引发严重的植物衰退甚至死亡，聚焦植物尤其是树木死亡的生理学机制并期望基于此评估及预测气候变化导致植物死亡风险已成为热点话题。植物通过调整内在生理代谢过程，例如通过调节渗透物质的含量，来平衡渗透势、维持细胞膨压、调节植物激素的信号水平，诱导植物气孔开放程度降低，有利于植物保存水分、调控植物水通道蛋白的表达，进而保持体内水分稳定并对干旱胁迫做出快速响应。这些生理过程中的每一环调节都为了确保水分运输的效率和安全性，增加植物抗旱性以及生态系统稳定性。植物的抗旱性不仅体现在生理代谢方面的调节，还表现在植物水力特性与解剖结构间相辅相成。当植物改变水力特性的同时，其茎叶会在解剖结构上做出调整以满足植物在干旱环境下水分供需平衡，从而降低植物蒸腾水分散失、增强细胞储水并提高生存能力。植物应对水分胁迫的策略通常与水分消耗和碳获取之间的平衡有关，明晰植物水分消耗与光合碳获取间存在平衡关系的性状特征便于更好地理解植物的水分利用策略。然而，植物表现出的任意单一性状特征的强弱都无法代表整个植物适应逆境的优劣，未来只有通过将植物更多性状特征进行相互关联，以具有代表植物水力功能、结...

Research progress from individual plant physiological response to ecological model prediction under drought stress

Abruptly global climate change has easily led to an alarming increase in drought events, resulting in severe plant decline and mortality. Consequently, there is an urgent need to investigate the physiological mechanisms underlying plant death, particularly in trees, and develop predictive models to assess and predict the risk of plant mortality due to climate change. Plants employ various physiological processes to mitigate the impact of water stress, including adjusting the content of osmotic substances to balance osmotic potential, maintaining cell turgor, regulating the signal level of plant hormones to reduce stomatal aperture, which is conducive to water conservation, modulating the expression of plant aquaporins, and thus maintaining water stability in the body and swiftly responding to drought stress. Each of these physiological processes is regulated to ensure the efficiency and safety of water transport, increasing plant drought resistance and ecosystem stability. Drought resistance in plants is not only reflected in the regulation of physiological metabolism, but also in the complementary relationship between hydraulic traits and anatomical structures. When plants modify hydraulic traits, their stems and leaves will adjust their anatomical structures to meet the balance of water supply and demand in drought environment, thereby reducing the transpiration water loss of plants, enhancing cell water storage and improving their survival ability. Strategies for coping with water stress in plants are often related to the balance between water consumption and carbon acquisition. Clarifying the characteristics of the equilibrium relationship between water use and photosynthetic carbon acquisition is instrumental to understand the water use strategies of plants better. However, the strength of any single trait displayed by plants can not represent the strength or weakness of the whole plant adaptation to adversity. In order to predict the survival risks and ecological distributions of different plants in drought environment on a large scale, it is essential to integrate a variety of interconnected traits into the model system in the future, with a focus on traits representing plant hydraulic function, structure and photosynthetic capacity. In this paper, we provide a comprehensive review of the physiological and metabolic mechanisms of plants under drought stress while elucidating the relationships among plant hydraulic traits, anatomical structures, and photosynthesis. On the basis of existing studies, it points out the important significance of the development of plant hydraulic models and promotes the application of comprehensive plant traits in hydraulic and other models. This provides a basis for assessing current ecosystem plant survival risks and future ecosystem health levels.