Abstract: The main objective of the experiment is to study the effect of cool temperature on the percentage of filled grains of rice. The results showed that daily mean temperature is the main temperature index; daily minimum temperature is the supplementary index during meiosis stage; and daily maximum temperature is the supplementary index during flowering stage.If the adverse effect of cool temperature during sensitive stages was serious,the effects could be accumulated.It would be better to calculate the critical cool temperature during flow- ering stage for both Japonica and Indica type of rice by using the average temperature value of successive three days. The critical values of cool temperature for early-maturing Indica, hybrid Indica, medium-maturing and late-maturing Japonica type of rices at flowering stage had been suggested. When rice was treated by the same.daily mean temperature but with dif- ferent range of temperature in a day at flowering stage, the percentage of filled grains was lowonclick="SelectDisplayDiv('EnDivSummaryMoreSummary','EnDivSummaryMore');DisplaySpanDiv('EnDivSummaryHuanYuan')"> if the temperature difference was too small or large.Among the meteological factors affecting the percentage of filled grains, temperature is the most important one;sunlight did not significantly affect it under cool temperature condition,but it negatively correlated with the percentage of filled grains under normal temperature condition. The relationship between the seed-set percentage and rainfall was not significant.

Key words: Rice, Cool injury, Seed-set percentage, Simulation, Temperature index

摘要： 本试验旨在探索秋季低温对水稻开花结实影响的若干不够明确的问题。结果表明:低温指标中,日平均温度是主要指标;日最低温度是减数分裂期的辅助指标;日最高温度是开花期的辅助指标。如在不同低温敏感期均受害较重,则低温危害表现为累加效应。计算低温临界温度时,籼粳稻均以连续三天的温度平均为好。提出了开花期籼稻、籼型杂交稻、中粳、晚粳四类型的低温临界值。开花期的日温差过大或过小均导致空瘪率上升。气象因子中,温度对空瘪率的影响最大;适温条件下,空瘪率与日照呈负相关:雨量与空瘪率关系不显著。

关键词: 水稻, 低温冷害, 结实率, 模拟, 温度指标