作物旱后复水补偿效应产生的源-库-流的响应及机制

Response and Mechanism of Source-Sink-Flow Caused by the Compensation Effect of Crop Rehydration After Drought

[目的]作物在生长过程,尤其在干旱半干旱地区,时常经受干旱和复水(降雨或灌溉)过程。干旱胁迫下作物的生长发育受到抑制,产量降低;同时,经过干旱胁迫后作物对干旱胁迫的耐受性有所提高;而干旱胁迫后复水,为了弥补作物干旱期间的损失,作物往往表现出补偿性生长,在产量上产生补偿甚至超补偿效应。作物旱后复水补偿效应是作物对干旱胁迫的积极响应与复水后补偿性生长的共同结果,在旱区作物生产中合理利用旱后复水补偿效应可以有效提升作物产量和水分利用效率。[方法]“源库”关系被广泛用来解释作物产量的形成过程,调控源库关系也是提高作物产量的重要途径。旱后复水补偿效应的产生与作物“源—库—流”响应关系密切。[结果]基于当前的研究进展,从“源库”关系总结作物旱后复水补偿作用产生的机制。在干旱胁迫过程中,源端表现为气孔关闭、光合降低、可溶性碳水化合物累积增加,而库端表现为库活性增加。复水后补偿效应产生过程中,在源端气孔打开、光合恢复、短时间内甚至高于干旱胁迫前,同时源端(叶片)可溶性碳水化合物代谢增强,促进作物光合作用,碳水化合物的合成能力提高;在库端(籽粒)库活性维持较高水平,同化物卸载和累积速度加快;同时流中同化物转运维持较高水平。在补偿效应产生的源—库响应中同化物的转运积累起着重要的作用,其中蔗糖转化酶(INV)、细胞壁转化酶(CW-INV)和聚糖代谢酶(1-FEH w3)活性在作物旱后复水补偿效应的源库响应过程中起着至关重要的作用。[结论]从源库关系角度对旱后复水补偿效应产生的机制进行较为深入的总结和分析,为理解作物旱后复水补偿效应产生的机制及旱区作物水分高效利用提供理论依据。

[Objective]Crops often suffer from interval drought and rehydration(rainfall or irrigation)during the whole growth period,especially in arid and semi-arid areas.Under drought stress,the growth and development of crops are inhibited,and the yield is reduced;meanwhile,the plants drought tolerance will be induced.In order to compensate loss of yield or growth induced by drought stress,crop often shows compensatory after rehydration,which produces compensation or even over compensation effect on yield.The compensation effect of post drought is the result of crop’s positive response to drought stress and compensatory growth after rehydration.It can effectively improve crop yield and water use efficiency in crop production in arid areas.[Methods]Source sink relationship is widely used to explain the crop yield formation,and regulating the source sink relationship is one of key way to improve crop yield.The compensation effect of post drought is highly related to the source sink response of crops.Based on the current research progress,this paper tries to explain the compensation effect of post drought in source and sink way.[Results]Under the drought stress,in the source,the stomata were closed,photosynthesis was decreased and soluble carbohydrate accumulation was increased,while sink activity was often increased.After rehydration,the metabolism of soluble carbohydrate in the source(leaf)was enhanced,which enhanced the photosynthesis and the ability of carbohydrate synthesis;meanwhile,the sink activity(grain)was maintained at a high level,and the rate of assimilate unloading and accumulation was accelerated;the assimilate in the flow remained at a high level.During this process,the activities of sucrose invertase(INV),cell wall invertase(CW-INV)and fructan exohydrolases(1-FEH w3)play important roles in the source sink response to the compensation effect of post-drought.[Conclusion]This paper integrated the mechanism of compensation effect of post drought in the perspective of source sink relationship,which provides a theoretical basis for understanding the mechanism of compensation effect of post drought and improving crop water efficient in arid areas.