超高产夏玉米根系对源库发育及性能的调控效应研究

With the development of industrialization,urbanization and people's living standards, China has entered a stage of rapid growth of corn consumption, and will be faced wiith shortages of corn in long time.In the condition of arable land continuous decrease, improving grain yield per unit area is the only way to increase total corn yield.Now,rational increase plant polulation is an effective measures to improve corn grain yield per unit area.Under high plant population, contradiction between photosynthesis source and grain sink, root and canopy become acutely. Which become key limitling factor for high and stable yield.Researches about corn sources, sinks and root in middle and lower yeild levels have been undertaken by many researchers. However, there are little researches putting aerial parts (sources and sink) and underground part (root) together as the study object under higher yield condition, especially for summer corn under high plant population. Our project aim to use different super high yield corn hybrids, with morphology, physiology and enzymology methods to study the capacities and activies of sucrose and sink of super-high yield corn and its response metabolism to root function regulations.And seeking regulation approaches of activities and balances between sources and sink. Our results will give support for formulating management measures of super-high yielding corn.

随着工业化、城镇化和人民生活水平的不断提高，我国已进入玉米消费快速增长阶段，将长期面临产不足需的问题。但在耕地面积刚性减少的情况下，玉米总产的提高必须依靠单产的持续增加。当前，玉米单产增加主要以合理密植为主，增密后源库、根冠矛盾更为突出，成为高产、稳产的关键限制因素。前人对普通玉米源库特征、根系功能等分别进行了研究，但超高产密植条件下根系对地上部源库发育及功能调控的研究鲜见报道。本项目以不同生产潜力的夏玉米品种为试材，采用形态学、生理学、酶学等相结合的方法，在探明超高产夏玉米源库建成规律的基础上，深入研究根系分布与功能对源库发育及性能的调控效应及其生理生化机理，为提出通过调节根系生长与功能，进而调节地上部光合源、籽粒库活性及与源库协调性的关键栽培技术措施提供理论依据与技术支持。

当前，玉米单产增加主要以合理密植为主，增密后源库、根冠矛盾更为突出，成为高产、稳产的关键限制因素。前人对普通玉米源库特征、根系功能等分别进行了研究，但超高产密植条件下根系对地上部源库发育及功能调控的研究鲜见报道。本项目以不同生产潜力的夏玉米品种登海661、郑单958和先玉335为试验材料，采用形态学、生理学、酶学、蛋白质组学等相结合的方法，比较研究了高产夏玉米的光合源、籽粒库发育与功能特征。其光合源具有叶片垂直占有率显著增加，有利于其群体内中低层、穗位层透光率增加，密植群体内蓝紫光降幅小、叶片衰老延迟、光合高值持续期长的特点；其籽粒库具有总小花分化数量多、灌浆起始势高、活跃灌浆期长、淀粉积累速率快、受密度影响小的特点。首次利用蛋白质组学技术分析了玉米籽粒发育过程中蛋白质的差异表达特性，揭示了密植夏玉米顶部弱势粒形成的生理生化与蛋白质组学机理。与强势籽粒相比，籽粒库容建成期弱势籽粒最大胚乳细胞增殖速率及平均增殖速率、最大胚乳细胞数目、籽粒库容量显著降低；弱势籽粒中细胞增殖相关蛋白显著滞后表达，淀粉合成相关蛋白显著下调表达，，弱势籽粒中低活性的糖酵解途径，减少了其物质合成所需的能量供应。采用横向和纵向断根的方式探明了夏玉米根系分布与功能对地上部叶片发育、光合性能及籽粒库容建成、灌浆的调控效应及其生理生化机理。初步探明了通过氮肥深层施用（本试验条件下以-15 cm最佳）改变根系构型、增加深层根系分布、改善根系解剖结构、降低根系呼吸速率，进而提高水、氮吸收效率，协同提高籽粒产量与氮肥利用效率的有效技术途径。