草地早熟禾（Poa pratensis L.）是我国及世界应用最多的优良冷季型草坪草，其重要持绿特性与氮利用效率和叶绿素代谢关系紧密。培育色泽浓绿且绿期长的节氮型新品种是草坪领域的研究热点。本项目基于前期草地早熟禾资源氮利用效率研究基础上，采用形态学、生理学及分子生物学等多学科的理论和先进技术，拟探索不同氮效型草地早熟禾持绿性差异的内在机理。主要研究内容有：草地早熟禾表型和细胞组织结构及生理代谢与持绿性的关系；通过转录组学和基因功能验证挖掘与持绿性相关的氮代谢和叶绿素代谢通路中的重要调控基因及其表达以及基因间的互作与功能；综合分析揭示不同氮效型品种持绿性差异的表型、代谢及基因调控的规律；筛选出绿期长，绿色度强且高效节肥特性的形态和理化指标及优良基因资源。研究成果对丰富植物叶绿素生物合成和降解、氮代谢等理论以及进一步利用基因改良提高草地早熟禾色泽和绿期及氮素利用效率具有重要理论和实际意义。

Kentucky bluegrass (Poa pratensis L) is the most widely used cold-season turfgrass in China and the world. The important trait of stay-green on it is closely related to nitrogen use efficiency and chlorophyll metabolism. Therefore, targets for breeding nitrogen-saving cultivar with dark green color and long green period holding capacity in turfgrass become the hotspot. According to our previous study on the nitrogen use efficiency in Kentucky bluegrass, the internal mechanism of the differences of green retention between different types of nitrogen use efficiency will be examined in morphology, physiology and molecular biology based on the multidisciplinary theories and advanced technologies.The research contents include: the associations of the stay-green traits with phenotype and cellular structure as well as physiological metabolism; to find the key regulating genes and their expressing patterns also including their functions in nitrogen and chlorophyll metabolic pathways relation to stay-green trait through transcriptomic and function verification for genes; through comprehensive analysis with their phenotype, metabolism and genes regulation, the mechanism of greenness holding differences in different nitrogen use efficient cultivars will be deciphered; the effective morphological and physicochemical indicators and excellent genetic resources with long green period versus strong green degree, and also with high nitrogen use efficiency will be screened out. Our research results could have important theoretical and practical significance for enriching the theory of plant chlorophyll and nitrogen metabolism, and could further to improve the turfgrass leaf color and greenness period as well as nitrogen use efficiency by genetic method.