中文摘要：

【目的】为明确氮素优化管理模式（OPTs）下水稻根系形态和生理特征及其与氮素吸收和产量形成的关系。【方法】以镇稻11为材料,采用营养液培养,通过三种氮素供应模式分别模拟农民习惯施肥（FFP）、高效施肥（HE）及高产高效施肥（HEHY）,研究了不同供氮模式对水稻主要生育期生物量和氮素累积、根系形态和生理特征以及产量形成的影响。【结果】与FFP相比,HE和HEHY（OPTs）通过提高每穗粒数、结实率和千粒重而使水稻籽粒产量分别增加5.7%和16.0%。与FFP相比,OPTs增加了生育期内水稻根系生物量、根系长度、根系总表面积、根系体积以及单个分蘖不定根数目,并提高了灌浆期根系活力、根系氮素同化能力以及叶片光合速率。相关分析表明,开花期根系生物量、总表面积、根体积、单个分蘖平均不定根数目、伤流液流速和谷氨酰胺合成酶活性均与总氮素累积量及产量显著正相关。【结论】因此,OPTs通过养分调控,可促进水稻根系的生长、优化根系形态结构,并能维持水稻生育后期较高的根系活力,从而促进了水稻对氮素的累积以及产量的形成。

英文摘要：

[Objective]The objectives were to study the effects of optimized N managements （OPTs, including HE and HYHE） on root growth, root morphological and physiological characteristics, and their relationships with N accumulation and yield formation. [Method]Hydroponic experiments using Zhendao 11 as material were conducted in a greenhouse with three N supply patterns： farmersr fertilizer practices （FFP, T1）, nitrogen （N） application of high efficiency （HE, T2）, and N application of high yield and high efficiency （HEHY, Ta）. [Result] Higher spikelet number per panicle, filled grain rate and 1000-grain weight were achieved in HE and HYHE treatments compared to FFP, which led to grain yield increase of 5.7% and 16.0% in HE and HEHY （OPTs）, respectively. Rice roots in OPTs had higher root dry matter weight, total root surface area, root volume, and adventitious roots number per tiller and longer root length throughout the growth season. OPTs resulted in higher xylem flow sap rate, root N assimilation activity, and leaf photosynthesis speed anthesis stage and middle grain filling stage. The root dry matter weight, length, total surface area, volume, and adventitious roots number per tiller, xylem flow sap rate, and root N assimilation activity had significantly positive relationship with total N accumulation and grain yield. [Conclusion]OPTs could improve root growth, optimize root morphology, and maintain higher root physiological activities, thus achieving the improvement in N accumulation and grain yield.