Abstract: In order to illuminate the ecological mechanisms of avoidance and resistance to heat injury of rice,a field experiment was conducted to study the effects of fertilization level on panicle temperature at the heading stage in two rice varieties with significant differences in canopy and population development from 2004 to 2005 in Yangzhou City,Jiangsu Province,China.It showed a changing trend similar to the atmospheric temperature with the highest temperature during 10:30 to 15:30.The average panicle temperature of three treatments(low,middle and high fertilization levels)in Yangdao 6 and Yangjing 9538 were 3.58℃ and 3.04℃ respectively lower than the atmospheric temperature.In addition,the discrepancy between air and panicle temperature at high and middle fertilization levels were 1.54℃ and 0.90℃ higher than that at the low fertilization level.The discrepancy between air and panicle temperature in Yangdao 6 was also 0.85℃ higher than that of Yangjing 9538 at the same fertilization level. The discrepancy between air and panicle temperature in the three treatments showed a negative relationship with the transmittance of panicle,but positive with total leaf area index(LAI),LAI above the panicle,biomass and number of culms and tillers.These results indicated that a good structure of rice canopy and population from optimized field management,e.g.reasonable fertilization level could decrease the panicle temperature,and increase the avoidance and resistance to heat injury.

Key words: rice, fertilization level, panicle temperature, population property, heat injury

摘要： 在田间环境下, 利用2个冠层结构差异显著的水稻品种（扬稻6号、 扬粳9538）, 设置高、 中、 低3个施肥水平, 研究水稻抽穗期穗部温度特征, 以探讨水稻抗热避热的生态学机制。 穗部与大气的温度变化趋势基本一致, 但扬稻6号和扬粳9538的穗部平均温度分别比气温低3.58℃和3.04℃。 施肥水平显著影响大气穗部的温度差, 高肥和中肥处理下, 2个品种的平均值分别比低肥的高1.54℃和0.90℃。 品种间大气穗部温度差也存在差异, 扬稻6号平均比扬粳9538高0.85℃。 相关分析发现, 不同施肥水平下大气穗部温度差与总叶面积指数、 穗上叶面积指数、 生物量和有效分蘖数呈极显著正相关, 而与穗部透光率呈极显著负相关。 说明通过优化田间管理比如合理的施肥来建立良好的群体结构, 对降低穗部温度, 提高水稻抗热避热能力的效应显著。

关键词: 水稻, 施肥水平, 穗部温度, 群体特征, 高温热害