根据2000年至2005年桂花(Osmanthus fragrans Lour.)盛花期的物候变化和开花前1~5周的气象资料,运用主成分分析法研究了影响南京地区桂花秋季开花的主要气候因子。结果显示,开花期与开花前周平均最低温度有较大关系,开花前4周的周平均最低温度持续走低有利于开花,尤其是开花前1周的周平均最低温度持续在18℃以下时,桂花进入盛花期。开花前适宜的降水增加了空气相对湿度,能促进开花;降水量过大则延迟开花。剧烈的气温波动不利于开花。该研究有助于预测秋天桂花的开花时间,为实现花期调控提供科学依据。

Using th eprincipal component analysis method, key climate factors influencing blooming of Osmanthus fragrans Lour. were investigated on the basis of phonological phenomena in full blooming period and meteorologic data of 1st to 5th week before blooming atautumn in Nanjing from 2000 to  2005. The results show that week-mean minimum temperature before blooming has a great effect on blooming of O. fragrans. Generally, the continually descending of average minimum temperature of the 4th week before blooming will facilitate blooming at autumn. When average minimum temperature of the 1st week before blooming persists is lower than 18℃ , O. fragrans will come into full blooming period. Moderate precipitation can increase relative air humidity, which is conducive to blooming; while too much precipitation will delay blooming time. Additionally, violent temperature fluctuation is harmful to blooming. These results are helpful for predicting blooming time of O. fragrans, and also can provide scientific basis for regulating blooming time.