小麦生产中过量施用氮肥导致生产效益降低、环境污染加剧，选育高产高效品种是提高氮肥利用率、确保粮食安全、保护生态环境的重要手段。研究表明，小麦品种演进过程中氮素吸收利用效率提高，但其机理尚不明确。本项目拟以长江中下游麦区有相似遗传背景的不同年代主推品种为材料，系统分析小麦根系形态的演变规律，明确植株内源激素平衡的变化特征及其对根系形态和根-冠物质分配的调控效应，探明氮素高效吸收利用的根系群体和根-冠平衡特征及其形成机理；分析根系衰老和生理活性的演变特征，明确小麦根系NO3-转运蛋白基因表达的演变规律及其调控机制，阐明根系吸收功能和氮素同化的演变机理，明晰氮素高效吸收利用的关键生理特性及其调控机制；分析品种更替中光合性能和碳代谢的演变规律，揭示光合性能演变与氮素吸收利用的关系，阐明小麦品种演进过程中氮素吸收利用演变的生理机理。研究结果将为小麦高产高效品种选育和栽培管理优化提供重要的理论依据。

Excessive nitrogen(N) fertilizer application in wheat production has become the main factor that induces the lower production benefit and severe environmental pollution. Breeding new cultivars with high yield and nitrogen use efficiency (NUE) can sufficiently improve the NUE and further ensure the food security and preserve ecological environment. Previous studies showed that N uptake and utilization efficiency improved during the cultivars genetic evolution, while their physiological mechanisms are still unclear. In this study, wheat cultivars share similar genetic background and have been widely planted in the Middle-Lower Yangtze River Basin in different decade were investigated in order to understand the mechanisms of root-shoot balance characteristics and formation of root population with high N uptake; To understand the relationship between nitrogen utilization and root morphology, phytohormone content and their relationships with root-shoot matter balance. Moreover, the characteristics of genetic evolution on root senescence and activity will be analyzed to reveal genetic evolution and regulation mechanism of root NO3- uptake carrier NRTs expression characteristics, root uptake ability, N assimilation and high utilization. The evolution of photosynthesis and carbon metabolism will be further analyzed to understand the relationship between N uptake and assimilation and to clarify the physiological and molecular mechanisms of genetic evolution on N uptake and utilization. Results could provide theoretical basis and technical support for breeding high yield and N efficiency cultivars and efficient production regulation in wheat.