水稻高产氮高效基因型的籽粒灌浆机理及其调控

In rice production in China, farmers used to apply excessive nitrogen fertilizer thus reduced nitrogen use efficiency, how to coordinate the high yield and high nitrogen use efficiency is very important now. Based on existing research, we chosed 3 kinds of rice cultivars :with high-yielding and high nitrogen use efficiency, with high-yielding and low nitrogen use efficiency(CK1) and with low-yielding and low-yielding , intending to carry out the following targeted research: (1) study and reveal genotypes differences of grains filling characteristics in different rice cultivars and its relationship with nitrogen use efficiency and yield, deeply study different indica rice genotypes grain starch, soluble sugar, starch synthesis key enzyme, hormone changes and their relationship with grain filling characteristics, to clarify the mechanism of grain filling of indica rice nitrogen efficiency genotype differences; (2) using the cultivars with high-yielding and high nitrogen as material, research and reveal leaves carbon, nitrogen metabolism characteristics variation under different nitrogen levels and light conditions, clear the relationship between leaves carbon, nitrogen metabolism characteristics and grain filling enrichment, and illustrates the mechanism that environmental factors, such as nitrogen and light regulate the grain filling. Based on the research results above, we try to reveal the grain filling mechanizm and regulation in rice with high-yielding and high use efficiency,to provide the theoretic basis for improving cultivars for high yield and high nitrogen use efficiency.

紧扣我国水稻生产中氮肥用量大、氮肥利用率低、高产与氮高效难以协调的重大实际问题，在已有研究的基础上，选用高产氮高效、高产氮低效（CK1）和低产氮低效(CK2)3种典型籼稻基因型为对象，开展以下针对性研究：（1）研究并揭示不同籼稻基因型强、弱势粒灌浆特性差异及其与氮素利用率和产量的关系；深入研究不同籼稻基因型籽粒库生理活性的变化及其与籽粒灌浆特性的关系，阐明籼稻氮效率基因型差异的籽粒灌浆充实机理；(2)以高产氮高效籼稻基因型为进一步研究对象,研究并揭示相同基因型、不同氮素水平与光照条件下叶片碳、氮代谢特征的变化特征，明确叶片碳、氮代谢特征变化与籽粒灌浆充实及氮素利用率的同步互动关系，进而阐明氮素、光照等环境因子对籼稻高产氮高效基因型籽粒灌浆充实的调控机制。综合以上结果，系统揭示籼稻高产氮高效基因型的籽粒灌浆机理及调控效应，为品种的合理改良和高产高效栽培提供理论支撑。

紧扣我国水稻生产中氮肥用量大、氮肥利用率低、高产与氮高效难以协调的重大实际问题，选用高产氮高效、高产氮中效（CK1）和低产氮低效(CK2)3种典型籼稻基因型为对象，研究水稻高产氮高效基因型强、弱势粒灌浆特性及其与氮素利用率和产量的关系；揭示水稻高产氮高效基因型籽粒库生理活性的变化及其与籽粒灌浆特性的关系，阐明籼稻氮效率基因型差异的籽粒灌浆充实机理；并研究了氮素、光照对水稻高产氮高效基因型籽粒灌浆充实的调控效应。.结果表明，强势粒的最大灌浆速率、达到最大灌浆速率时的米粒重及平均灌浆速率均以高产氮高效品种>高产氮中效品种>低产氮低效品种，起始生长势、活跃灌浆期和有效灌浆时间均以高产氮高效品种<高产氮中效品种<低产氮低效品种；弱势粒的最大灌浆速率、达到最大灌浆速率时的米粒重及平均灌浆速率均以高产氮高效品种>低产氮低效品种>高产氮中效品种，起始生长势、活跃灌浆期和有效灌浆时间均以高产氮高效品种<低产氮低效品种<高产氮低效品种。高产氮高效型品种不论强弱势粒均具有灌浆启动早、灌浆速率快、有效灌浆时间短等特点；高产氮中效型品种强势粒灌浆充实较好，但弱势粒灌浆启动慢、灌浆速率低、有效灌浆时间长，这是限制高产品种氮效率进一步提升的重要原因。灌浆充实度差异的根本原因是籽粒生理活性差异。高产类型品种灌浆前中期籽粒中淀粉合成相关酶活性更高，相关激素含量与籽粒灌浆速率基本同步或稍前。高产氮高效品种和高产氮中效品种的强势粒相关酶活性及激素含量差异总体上较小，但弱势粒差异较大，高产氮高效型品种在灌浆前中期具有更高的淀粉合成关键酶活性和更高的激素含量。不同氮素条件下高产氮高效水稻品种的籽粒灌浆特性存在较大差异，中氮条件下籽粒强弱势粒灌浆充实较好，低氮条件下籽粒强势粒灌浆速率低，高氮条件下弱势粒灌浆启动慢、速率低。不同遮光条件均降低高产氮高效品种籽粒灌浆速率和米粒最终生长量。