半高秆高生物产量型超级杂交稻抗倒伏形态及生理协同机制的研究

In the program of the Super hybrid rice breeding, by utilizing semi-high-stem to obtain the high biomass for super high yield has become an important trend but the lodging is one of the important limiting factors. Therefore, we firstly integrate "semi-high-stem" with high biomass yield to study the collaborative mechanisms between rice morphology and physiology in the lodging resistance. Based on the comparative studies of the morphological and physiological differences between 1st, 2nd and 3rd phase super-hybrid rice varieties, we focus on the rice hybrids typed in the semi-high-stem" with high biomass to study on the morphological changes, and the variation with the dry matter absorption and transportation rate of stems and sheath, silicon, cellulose, IAA and GA4 in physiological and biochemical differences. And it finds out the relationship and collaboration mechanisms in "morphology, physiology & lodging resistance capacity" and "nitrogen nutrition, growth regulation, lodging resistance capacity" of the type of the "semi-high-stem" super hybrid rice. Try to establish key morphological and physiological indicator system for the type of the "semi-high-stem" super hybrid rice to provide theoretical and technical basis for super hybrid rice breeding and cultivation.

超级杂交稻育种向半高秆转变以获取高生物产量实现超高产目标，已成为一个重要趋势，而倒伏是其重要限制因子之一。因此，本研究首次把"半高秆与高生物产量"作为整体，研究水稻抗倒伏形态与生理协同机制，在比较现有第一、二、三期超级杂交稻抗倒伏形态与生理基础上，重点研究"半高秆高生物产量型"杂交组合的形态差异，以茎鞘物质撤退，硅、纤维素差异为核心的生理生化差异与抗倒伏关系，并探讨对节间伸长与物质运转有关的内源激素GA和IAA的差异，明晰"半高秆高生物产量型"杂交稻"植株形态－生理－抗倒能力"及"氮素营养－生长调控－抗倒能力"的相互关系与协同机制，为超级杂交稻向半高秆转变进一步高产育种和超高产栽培提供理论与技术依据。

超级杂交稻育种向半高秆转变以获取高生物产量实现超高产目标，已成为一个重要趋势，而倒伏是其重要限制因子之一。本项目基于超高产育种现状与趋势，首次把“半高秆与高生物产量”作为整体，设置5个方面的内容开展水稻抗倒伏形态与生理协同机制研究，在比较第一、二、三期超级杂交稻茎秆形态结构及抗倒能力差异基础上，重点研究“半高秆高生物产量型”杂交稻茎秆形态结构、抗倒关键生理指标、节间伸长有关的激素GA和IAA差异及其新型抗倒调控剂调环酸钙的调控机制、不同氮肥用量的养分管理技术对抗倒性影响。. 研究表明超级杂交稻在产量不断递进过程中品种的选育更注重了节间的合理配置，使产量在不断递进过程中能够保持抗倒性，并初步明确了“半高秆高生物产量型”杂交稻的形态指标体系为株高适中（120cm左右）、节间配置合理，穗下节间长，基部节间短、粗、厚，高度抗倒。水稻植株的倒伏指数与株高、重心高度、重心相对高度呈正相关，与节间粗度、节间壁厚、基部节间大/小维管束面积及数目均呈负相关。株高并不是影响倒伏的唯一因素，在一定的范围内合理的节间配置能够通过保持株高增加其生物量，还有利于抗倒伏。茎秆干物质重较高、茎鞘物质输出率相对较低、 C/N、可溶性糖、纤维素、木质素、全钾、全硅等关键生理指标含量高有利于提高植株抗倒伏能力。节间伸长启动期IAA含量与节间长度及节位关系最密切，调环酸钙可以降低IAA和GA1含量，使株高、穗长及基部节间缩短，增加生物量、茎秆粗度、茎壁厚度、C/N、可溶性糖、全钾、全硅、木质素、纤维素等含量，有利于提高抗折力，且对产量没有显著影响。增施氮肥增加倒伏指数及株高，降低茎壁厚度、C/N、全钾、全硅、可溶性糖、木质素含量。该研究为超级稻实现亩产1000kg提供了技术支撑，为超级杂交稻向半高秆转变的育种和抗倒超高产栽培提供理论指导与技术依据。