红树植物在长期演化中进化出一系列适应高盐和水淹环境的生存策略，是研究植物耐盐和耐水淹代谢及分子机制的理想材料。红树植物的根系对盐度和水淹胁迫的响应至关重要。本项目以我国分布最广的真盐生红树植物秋茄为对象，运用TEM、LSCM、NMT等手段研究不同盐—水淹环境中其根系在器官、组织和细胞水平上的结构变化，以及Na+和K+的积累分布规律和实时转运特性；运用高分辨率串联质谱（AB SCIEX Triple TOF 5600+）技术，研究盐—水淹胁迫下根系代谢谱变化，筛选差异显著代谢物，揭示关键代谢途径，并利用高通量测序技术进行转录调控分析和差异基因筛选，阐明水淹和盐度交互作用下根系Na+和K+转运和积累与根系关键代谢物的关联，及相关基因的调控特征。本研究的实施可为红树植物根系响应盐—水淹胁迫生境的地下过程提供新的认识，为耐盐、耐水淹基因的挖掘和利用提供参考。

Plant metabolites enable plants to grow under harsh environment by modulating the plant's own protective mechanisms and coordinating the plant's interactions with the environment. The angroves, a unique and endangered ecosystem in the intertidal zone, can not only endure high salinity, but also are adaptive to waterlogging caused by the tides. The mangroves which possess a series of special survival strategies under the salt and water logging environment after they evolved specific salt and flood tolerance mechanisms during the long-term evolution, are ideal materials for studying and dissecting the salt-flood tolerance metabolism mechanism and molecular regulation mechanism. Naturally, the root system of mangrove plants is critical to the response to salinity and flooding stress. This project aims at the most widely distributed real mangrove plant in China, and uses the cutting-edge technology (e.g., Transmission Electron Microscope, Laser Scanning Confocal Microscopy, and Non-invasive Micro-test Technology) to investigate the structural changes of root at organ，tissue and cell level in different salt-flooded environments through a manipulative experiment. The long-term accumulation and distribution as well as the instantaneous changes of Na+ and K+ will be examined under different salinity and waterlongging environments. Advanced AB SCIEX Triple TOF 5600+ techniques will be used to study the metabolic profile changes under salinity and waterlongging stress, based on which we will screen for significant changed metabolites, and then identify key metabolites and metabolic pathways involved in salt and flood tolerance. In addition, high throughput sequencing technology will be used to analyze the gene expression under salt-flood stress condition and screening for differential expressed genes. The purpose is to elucidate the relationship between root Na + and K + transport and accumulation and root key metabolites under the interaction of flooding and salinity, and the regulatory characteristics of related genes. The implementation of this study can provide a new understanding for the underground processes of mangrove root response salt-flooding stress habitats and provide scientific basis for facilitating selection of elite germ-plasma resources from salt and waterlongging tolerance plants.