花后物质分配对水稻茎秆抗倒性能的影响及其调控途径

Rice is one of the most important stable grain crops in china. This calls for the need to increase and sustain rice production to ensure food security in the country. Distribution of biomass is one of the factors that have effect on the entire growth and development of the plant. Biomass partitioning after anthesis has not only been closely related to grain filling but also stem lodging resistance. However until date, it is still not completely clear how biomass partitioning after anthesis affect stem lodging resistance in rice, and the effective regulation paths. Based on the previous researches, the improvement of the biomass partitioning after anthesis is still the primarily technical path for high-yielding rice breeding and high efficiency cultivation. Field and pots experiments were set up to investigate the trend of biomass accumulation and distribution after anthesis and how this impact the stem lodging resistance. In this project, we regulated the stems biomass distribution by using gradient pollinating in female sterile line of three-line hybrid rice. Stem lodging resistance, carbohydrates accumulation and distribution characteristics of its components (e. g. soluble sugars, starch, cellulose and lignin) were measured during the grain filling. The objectives were to reveal the regulation paths of nitrogen on the carbohydrate components and proportion, and explore the effective methods for high-yielding with greater lodging resistance in rice, finally provide the theoretical and technical supports for high-yielding cultivation with stable increasing and higher resource efficiency.

水稻是我国最重要的口粮作物，持续稳定提高水稻单产是确保国家“口粮绝对安全”的根本选择。通过品种改良和农艺改进，提高花后干物质向籽粒转运是进一步提高水稻单产的有效途径。众所周知，花后物质分配不仅影响籽粒充实，而且与茎秆的抗倒性能密切相关。但是，目前有关花后茎鞘中物质再分配对茎秆抗倒性能的影响机制及栽培调控途径尚不太清楚。为此，本申请拟以水稻花后物质积累和分配规律作为切入点，采用田间试验和盆栽试验相结合的方法，对三系杂交稻不育系母本进行梯度授粉，以调控花后同化物在各器官中的分配，重点监测花后关键时期茎秆的抗倒性能、茎鞘中物质积累和转运规律以及碳水化合物各组分动态变化规律，明确氮素对茎鞘中物质再分配特性和茎秆充实特性的影响机制，揭示氮素对茎鞘中碳水化合物组分含量及比重的调控效应，探明水稻高产抗倒的栽培调控途径，为水稻增产稳产、资源高效栽培提供理论参考和技术途径。

本研究以水稻花后物质积累和分配规律作为切入点，采用田间试验和盆栽试验相结合的方法，对三系杂交稻不育系母本进行梯度授粉，以调控花后同化物在各器官中的分配，同时采用氮素构建不同产量水平水稻群体，比较了花后关键时期茎秆的抗倒性能、茎鞘中物质积累和转运规律以及碳水化合物各组分动态变化规律，明确氮素对茎鞘中物质再分配特性和茎秆充实特性的影响机制。结果表明，通过梯度授粉，构建了不同库容量水稻个体，效果显著。结合高产水稻品种，增加齐穗期茎秆中结构性碳水化合物积累（纤维素和木质素），有利于基部茎秆在灌浆后期维持茎秆强度。相关成果发表论文2篇，授权实用新型专利1项。课题实施过程培养研究生1人，参加学术会议3次。本项目为水稻高产抗倒协同提供了技术支撑。