微咸水灌溉下冬小麦生理生长响应特征与调节机制

The rational development of shallow underground brackish water for agricultural irrigation, not only can solve the problem of water shortage, but also can descend underground water level to reduce the soil secondary salinization hazards, meanwhile, soil and water environment for crop growrh will be improved. According to the basic theory in the field of frontier and hot issues. in this paper, we take several methods, including field trials, barrel experiments, chemical analysis and numerical simulation, The effects of different irrigation quota and different salinity brackish water irrigation on winter wheat growth, physiological and biochemical processes are researched. Additionally, the variation rules of winter wheat growth process, physiological effects of moisture variation, photosynthesis, chlorophyll fluorescence characteristics, osmotic adjustment and endogenous hormones and other indicators, are analysed from multi-scale, including crop groups, blades and cell scale. Which can illustrate the basic reasons of water budget, stomatal movement, photosynthetic fluorescence, morphological development and other changes of winter wheat under the influence of drought and salt stress. Response characteristics of winter wheat will be revealed, also the salt-tolerance mechanism and regulation mechanism under slight saline water irrigation. Through years of our work, we attempt to propose suitable slight saline water irrigation quota of winter wheat in Yellow River Delta, where reasonable water and salt control technology systems also will be established. Finally, the research can provide scientific basis for establish reasonable brackish water irrigation strategies of winter wheat in shallow groundwater areas, which also have important significance for Alleviation of freshwater shortage, Providing additional irrigation water, drought resistance and yield improvement.

合理开发浅埋区地下微咸水用于灌溉不仅可以解决水资源短缺的问题，而且可以通过降低地下水位减轻土壤次生盐碱化，改善作物生长的水土环境。针对该领域的基础理论和前沿热点问题，本课题拟采用大田试验、桶栽试验、室内化验和数值模拟等手段，研究不同灌溉定额和不同矿化度微咸水灌溉对冬小麦生长、生理、生化进程的影响，从作物群体、叶片、细胞多尺度分析冬小麦生长发育、水分生理效应、光合作用、叶绿素荧光特征、渗透调节以及内源激素等指标的变化规律，阐明水分和盐分互作下冬小麦水分盈亏、气孔运动、光合荧光、形态发育等变化的根本原因与内在联系，揭示微咸水灌溉下冬小麦生理生长响应特征及其耐盐机理与调节机制，提出黄河三角洲地区冬小麦适宜的微咸水灌溉定额，构建合理的水盐调控技术体系。研究结果为地下水浅埋区制定冬小麦节水、控盐、稳产的微咸水灌溉策略提供科学依据，对于缓解淡水资源短缺、增辟灌溉水源、抗旱增产具有重要的意义。

为了寻求合理的微咸水利用方式以及揭示微咸水灌溉下冬小麦生理生长响应特征与调节机制，在黄河三角洲典型区域开展了2年的试验研究，采用大田试验、桶栽试验、室内化验和数值模拟等手段，从群体、叶片、细胞多尺度研究微咸水灌溉对冬小麦生长、生理、生化进程的影响规律，结果表明：（1）采用3g/L的微咸水进行灌溉可以有效的提高土壤的含水率，对土壤盐分也有着一定的淋洗作用，使得冬小麦根区土壤的盐分向下运移，土壤剖面含盐量呈现出“S形”或“反S”的变化规律。微咸水灌溉导致了土壤盐分的增加，主要累积在0~40 cm表层土壤，两次灌溉盐分累积大于三次灌溉。（2）微咸水灌溉会抑制株高的增长和干物质的累积，而灌浆期不灌水则会使得LAI下降，但会促进冬小麦根系的生长。对比两次灌溉，三次灌溉可以缓解作物的水分胁迫，增加作物的灌浆速率，延长灌浆时间，3g/L的微咸水灌溉可以保证冬小麦的最终产量。（3）微咸水灌溉会影响叶片的功能及光合作用。3g/L的微咸水对叶绿素的影响较小，5g/L的微咸水则会使得叶片叶绿素含量降低。在拔节期采用3g/L的微咸水进行灌溉，可以促进冬小麦的生理生长，适当的盐分胁迫会促进光合作用。微咸水灌溉初期对光合作用的影响以气孔因素为主，随着盐分进入土壤根区，盐分胁迫对光合作用的影响则以非气孔因素为主，盐分胁迫抑制了叶片的活性，降低了冬小麦的光合作用。（4）微咸水灌溉会改变作物对有效光辐射的利用方式， 3g/L的微咸水灌溉会促进冬小麦对低有效光辐射的利用效率。5g/L的微咸水进行灌溉会影响冬小麦的叶片结构，降低叶片对高有效光辐射的响应，最终导致光合作用下降。另外，微咸水灌溉会增加冬小麦初始荧光，降低叶片的最大荧光产量和内禀光能转换效率。3g/L的微咸水一定程度上可以缓解作物的水分胁迫，并能提升作物在盐分胁迫下的光合效应。（5）冬小麦通过改变离子浓度与可溶物质浓度进行抗盐调节。当土壤盐分过高时，冬小麦会将大量Na+固定在根系之中，减少Na+对地上部分的影响。同时作物的K+会上升，以增加抗盐性。脯氨酸与可溶性糖的含量在作物受到高盐分胁迫时都会明显的增加，当冬小麦体内离子浓度过高时，作物会增加可溶物质的合成可以减轻作物“离子中毒”情况。综上，淡水-微咸水-微咸水的灌溉模式用于黄河三角洲地区冬小麦灌溉是可行的，既可以节约淡水资源，又能维持土壤水盐平衡，保证作物的产量。