植物水分传输过程中的调控机制研究进展

农田土壤水分的转化利用与调控是以土壤-植物-大气连续体(SPAC)为基础，以植物为核心，其中水分在植物体内的传输与调控研究一直是国际学术研究的前沿性热点课题。本文概述了植物水分传输的驱动力和传输途径，重点从植物的气孔调节、水容调节、渗透调节、水孔蛋白调节、贮水调节、气穴和栓塞调节等方面综述了植物水分传输过程中的调控机制研究进展。通过对植物存在优化调控水分平衡的潜在能力的研究，不仅可充实SPAC系统水分传输理论，而且有助于明确植物对环境的适应机制和高效用水的潜力及其节水调控的效应，对指导干旱半干旱地区农业生产提供理论依据。

Research progress on regulation mechanism for the process of water transport in plants

Water is the key factor affecting plant growth in the arid and semiarid regions. Facing the shortage of water resources and drought stress, traditional agricultural production method must be turned to higher efficient water-saving agricultural method, which can reduce the contradiction of agricultural water supply and demand, realize sustainable utilization of water resources and agricultural development. The use and regulation of soil water are based on soil-plant-atmosphere continuum (SPAC) in field and plants are the center in the SPAC system, water transport and regulation in plants is the focus and hot topic subject in this respect . This paper summarized the research advances on the process of water transport and regulation in plant, mainly about stomata effect, the regulation mechanism of plant water capacitance, osmotic regulation, aquaporin, storage, cavitation and embolism. Many references about plant water transport are analyzed to conclude that stomata plays the important role in regulating the process of water loss in plants, and it is a valve to control water loss from leaves when subjected to different soil and environmental factors. Stomatal regulation in plants is the result of combined effect of chemical and hydraulic signals. Water capacity is an important parameter that reflects water dynamic property of water transport in SPAC system and it plays an important role in regulating and controlling plant water storage and release ability anytime. The regulation of water capacity is a security mechanism of plant adaptation to environment with plants take up, transport and lose water when environmental factors change rapidly, water capacity prevents water loss in the xylem immediately, but is only the process of reduced water potential, thus water capacity improves plant resistance embolization ability. Accumulation of compound substances in plants have a improtment role in the osmoregulation process, and the accumulated osmoregulation substances in plants can scavenge oxidative radicals, improve permeability potential and enzymatic activity and balance excessive ions etc, which is beneficial for the osmotic regulation. The aquaporins could improve water transport across the membrane, enhance cell membrane for water permeability, regulate the cell penetration potential, increase transmembrane flow rate and hydraulic conductivity. Regulation mechanism of aquaporins is that it changes the membrane of molecule protein and the activity and synthetic rate of molecule protein and then regulates the transmembrane water flow. For example, drought lead to lower activity of aquaporins in root cells, so aquaporins is beneficial to limit soil water loss under drought and increase the drought-resistance ability. The resistance of water storage, water capacity and volume determine the regulation ability of water storage in every part of plant. The decreased resistance of water storage and increased water capacity and the volume improve regulation ability of water storage. When plants suffer from water stress, water tension of xylem gradually increases. And air goes into the conduit by conduit wall, and forms cavitation and embolism with the increase of cavitation, which decreases hydraulic conductivity when the tension is over a certain value. Thus, studying the regulating ability of optimal water balance not only can improve water transport theory in SPAC, but also can better understand plant adaptation mechanism to the environment and high water use efficiency and the regulation effect of water-saving, which provides scientific basis for alternate partial root-zone irrigation and biological water-saving technology.