旱后复水对小麦灌浆期物质转运的调控机制

Recent researches on the wheat water-saving principle indicated that dry matter transportation may play an important role in grain yield improvement under the post drought, such a gene regulating mechanism, however, still not yet linked with crop reproductive process. One of the biggest challenges for the drought-tolerant transgenic technology is to develop new varieties which will be good at both drought-tolerance under stress to get considerable biomass and maximizing to transport carbonhydrate to the harvest organ under rewatering, and to eliminate negative correlations btween crop drought tolerance and productivity. Effect of increasing yield through irrigation or rewatering has been confirmed by large amount of field experiments and farming practices, but its physiological and molecular mechanism of regulating dry matter transportation not yet clearly understood. This project focuses on the regulating mechanism of carbohydrate transport enzyme activities and relative gene expression in the grain filling precess under the post-drought rewatering conditions. The relationship among enzyme activities, relative gene expressions, grain yield performace and dry matter remobilization will be studied. The contribution of enzyme types and activities in the leaf, stem, spike, seed and grain yield will be evaluated. This project strongly links the physiological and molecular mechanism of water-saving irrigation upto the crop yield formation process under the water limited environments of the agricutural practices. The project will probably get new advance in the crop water-saving research and will provide scientific and guidance principles in the future wheat production of water limited areas.

小麦抗旱节水机理研究的一些新近结果表明，花后干物质转运有可能对于提高籽粒产量起着重要作用，但尚未见到旱后复水与产量形成基因调控相关的系统研究报导。当前抗旱转基因技术面临的主要挑战之一就是要培育既能够在干旱下存活并形成可观的干物质又能够在干旱解除后尽可能的将干物质转运到收获器官，从而消除抗旱性和丰产性之间的负相关关系。尽管旱后复水的增产效果已被大量的田间实验和生产实践所证实，但其调控物质转运的生理与分子机制仍不清楚。本项目主要研究旱后复水条件下小麦灌浆期物质转运关键酶及其基因表达与籽粒产量之间的关系，查明不同转运酶种类及其活力对籽粒产量的贡献程度，探索旱后复水对小麦光合同化产物积累分配的生理调控机制。本项目将作物抗旱节水的微观研究与我国水资源短缺条件下的作物产量形成过程密衔接起来，有可能在节水灌溉的应用基础研究方面取得新的进展，并为指导缺水地区的小麦生产提供科学依据和指导原则。

本项目以黄土高原旱地农业代表性的冬小麦品种为材料，通过不同生育时期的不同程度干旱处理，针对灌浆过程中营养器官与收获器官的物质分配问题，主要研究了碳水化合物转运酶系统在旱后复水的恢复生长过程中对小麦灌浆过程物质运输的调控机制，阐明了这些物质转运关键酶及其基因表达与籽粒产量之间的关系，查清了不同转运酶种类及其活力对籽粒产量、水分利用效率和收获指数的贡献程度。在旱后复水与不同氮素水平条件对小麦灌浆过程中营养器官与收获器官的物质分配比例、主要碳水化合物转运酶系统在旱后复水的恢复生长过程中对小麦灌浆过程物质积累与转运的调控过程、这些物质转运关键酶活性与籽粒产量之间的关系、不同转运酶种类及其活力对籽粒产量和水分利用效率以及收获指数的响应机制等方面取得明显进展。积极开展了中韩关于植物抗氧化基因工程的学术交流与国际合作研究，包括开展转基因作物抗旱节水机制的国际交流与合作研究。上述结果为指导缺水地区和旱作地区的小麦高产高效提供科学依据，并为我国旱地农业和节水农业提供指导原则。按照项目的实施计划，三年来，全面完成了研究任务，实现了本项目的预定目标，共发表标记本项目的学术论文16篇，其中SCI论文6篇，核心期刊10篇。