番茄气孔和光合过程对水盐耦合胁迫响应的生理机制与模拟

Water scarcity and soil salinization are the main environmental factors that limit crop productivity in arid and semi-arid areas. Improving water use efficiency or photosynthetic efficiency is vital to ensure food security. A deep and systemic understanding of the responses of crop photosynthesis and stomata to water scarcity and soil salinization is the key to improve water use efficiency or photosynthetic efficiency. This project intends to reveal the effects of drought and salt stress on stomatal structure and distribution, and the mechanism of photosynthesis biochemical processes and energy metabolism by monitoring the photosynthetic rate, stomatal conductance, transpiration rate, chlorophyll fluorescence, CO2 and light response curves, carbon isotope ratio, Na+ concentration, peroxidase activity, chlorophyll content, water potential and other indicators of tomato leaves under different water and salt stress. Based on these mechanisms, a coupled photosynthesis-stomatal conductance-transpiration model is proposed by combining the biochemical and physical processes of photosynthesis, physical processes of transpiration, leaf energy balance with optimal stomatal regulation under water and salt stress. The photosynthetic rate, stomatal conductance and transpiration rate under drought and salt stress would be simulated and predicted accurately by the coupled model. The scientific basis and guidance will be provided for completing the theory of responses to drought and salt stress in plant and precise regulation of crop water and salt conditions in root zone through this project.

在干旱半干旱地区，水资源短缺和土壤盐渍化是限制作物生产力的主要环境因素，提高水分利用效率或光合效率是解决食物安全问题的重要途径，而深入了解作物气孔和光合作用过程对水盐响应的生理机制则是提高水分利用效率或光合效率的关键。本课题拟通过监测西北旱区不同水盐耦合胁迫处理下番茄叶片光合速率、气孔导度、叶绿素荧光、CO2和光响应曲线、稳定碳同位素、Na+浓度、过氧化物酶活性、叶绿素含量、水势等指标，阐明水盐耦合胁迫对气孔结构与分布的影响，揭示水盐耦合胁迫对作物光合作用生化过程以及能量代谢影响的生理学机制。在机理认识的基础上，耦合光合作用生化和物理过程、蒸腾作用物理过程、叶片能量平衡和气孔优化调控等多过程的水盐耦合胁迫-光合-气孔-蒸腾机理模型，以实现极旱高盐条件下光合速率、气孔导度、蒸腾速率的准确模拟和预报。通过本项目研究，为完善作物水盐响应基础理论和实现作物根区水盐精准调控提供科学依据和指导。