Abstract: Taking a medium season japonica variety Wuyujing 3 and a medium season hybrid rice Shanyou 63 as experimental materials, the populations with different percentages of panicle bearing tillers and stems were formed by different planting density and N fertilizer applying treatment. The relationship between source quality at heading stage and its influencing factors were studied.For rice population with high grain yield, at heading stage, LAI was appropriate, rate of effective leaf area was high, rate of highly effective leaf area is from 75% to 78%. And during filling period, photosynthetic potential is higher than 2.10×10 6 m²·d,photosynthetic potential|grain ratio was higher than 47 cm²·d/spikelet. Photosynthetic potential|grain ratio(ratio of photosynthetic potential after heading versus the total quantity of spikelets) reflected the developing relationship dynamically of source|sink after heading, it is a better indication for source and sink quality during period of economic yield formation. Under conditions of these experiments, applying panicle fertilizer and so on based on the appropriate leaf area at heading stage would be effective measures for reducing the declining rate of leaf area, increasing the photosynthetic potential and photosynthetic potential grain ratio, and obtaining further higher grain yield.

Key words: rice, heading stage, source sink relations, nitrogen, yield, photosynthesis

摘要： 以中粳稻武育粳3 号和杂交中籼稻汕优63 为材料, 采用不同密度、施肥等栽培措施, 形成成穗率不同的群体, 研究水稻抽穗期源质量与产量关系及其影响因素。结果表明: 水稻高产群体抽穗期叶面积指数(LAI) 适宜, 有效叶面积率高, 高效叶面积率为75%～80% , 灌浆期光合势在2. 10×10 ⁶ m²·d 以上, 势粒比在47 cm²·d 粒以上。势粒比(光合势与总颖花量的比值) 能反映抽穗后群体源库发展动态的优劣, 是经济产量形成期源库质量的较好表述。本试验条件下, 通过穗肥等措施,在抽穗期适宜叶面积基础上, 降低抽穗后叶面积下降速率, 提高光合势和势粒比是进一步提高产量的有效途径。

关键词: 水稻, 抽穗期, 源库关系, 氮素, 产量, 光合作用