【目的】探讨水稻分蘖早发特性的品种间差异及其氮素调控效应，为丰产高效水稻品种的选育和栽培调控提供理论依据。【方法】采用盆栽试验，以分蘖速度有较大差异的不同类型水稻品种为材料，设置分蘖期不同供氮水平，分析水稻分蘖特性及光合同化、根系活力、植株氮浓度、分蘖节激素含量等农艺生理性状的品种间差异及其对氮素的响应。【结果】根据最大分蘖数和分蘖发生速率的差异，汕优63、两优培九和R3012表现为分蘖早发，扬稻6号表现居中，两个粳稻品种淮稻5号和南粳9108则表现为分蘖较慢。分蘖早发品种的分蘖特性对氮素较其他品种敏感。分蘖早发品种的生物量、每盆穗数和产量，分蘖期的植株氮浓度、氮代谢关键酶活性、叶片光合速率、根系氧化力和伤流量均显著高于其他品种，根系较为发达，分蘖节生长素含量较低，细胞分裂素含量则高于其他品种。分蘖早发品种相关农艺和生理性状对氮素也普遍较其他品种敏感。在各类型品种中也可见同样趋势的品种差异。【结论】较强的光合生产能力和根系活力，较强的氮代谢相关酶活性以及分蘖节较低的生长素、独脚金内酯含量和较高的细胞分裂素含量是水稻品种分蘖早发的重要生理机制。

【Objective】This study was conducted to explore the physiological mechanisms underlying inter-varietal differences in early-tillering characteristics and their responses to nitrogen, laying a theoretical basis for the breeding and cultivation of high-yield, high-efficiency rice varieties.【Method】A pot experiment was carried out using different rice varieties that exhibit significant differences in tillering speed at various nitrogen supply levels. The varietal differences in tillering characteristics and associated agronomic and physiological traits were analyzed, including biomass accumulation, yield and yield components, photosynthetic assimilation, root activity, plant nitrogen concentration, hormone contents in tillering nodes, and their responses to nitrogen.【Result】Based on the maximum number of tillers and tillering speed, Shanyou 63, Liangyoupeijiu, and R3012 were identified as early-tillering varieties, while Yangdao 6 was classified as a variety with general tillering speed. Huaidao 5 and Nanjing 9108 were classified as late tillering varieties. The early-tillering varieties were more sensitive to nitrogen supply. The biomass, number of panicles per pot, and yield of the early-tillering varieties, along with plant nitrogen concentration, activity of key enzymes involved in nitrogen metabolism, leaf photosynthetic rate, root oxidation capacity, and bleeding flow at the tillering stage, were significantly higher than those of the other varieties. The root systems of these varieties were more developed compared to others, with lower auxin content and higher cytokinin content in the tillering nodes. The responses of these agronomic and physiological traits to nitrogen in the early-tillering varieties were more sensitive. Similar trends in varietal differences were observed across various types of rice varieties.【Conclusion】High photosynthetic rates, enhanced root activity, elevated activities of key enzymes involved in nitrogen metabolism, low auxin content, and high cytokinin content in the tillering nodes are important mechanisms that accelerate tillering in rice.