ABSTRACT

The effects of controlling night temperatures (NTs) during summer-season on flowering and photosynthetic characteristics in Chrysanthemum morifolium were investigated at NTs of 20, 23, 26, or 29°C and a day temperature (DT) of 35°C. Days to budding and flowering increased more in the plants grown at NTs of 26 or 29°C than those of 20 or 23°C, regardless of cultivar. The flowers appeared as a withered state in ‘Swifty Rosso’ grown at a 26°C NT and ‘Swifty Yellow’ at 26 or 29°C NTs. The percentage of abnormal flowers reached 100% in ‘Swifty Rosso’ grown at a 26°C NT and 26 and 29°C NTs in ‘Swifty Yellow’. Flower size were the largest in the plants grown at 20 or 23°C NTs than those at 26 and 29°C NTs. The net CO₂ assimilation rates had average high values in the plants grown at 20 or 23°C NTs. Low photosynthetic efficiency was found in the plants grown at 26 or 29°C NTs. At the high DT that occurs during the summer season with high NTs ≥26°C delays budding and causes abnormal and withered flowering. Since it is year-around plant, techniques of controlling NTs can be used effectively while maintaining quality levels.

摘要

 在20、23、26或29°C的NTs和35°C的日间温度（DT）下研究了夏季控制夜温（NTs）对菊花的开花和光合特性的影响。在NTs为26或29°C下生长的植物中，出芽和开花的天数比20或23°C下的增长更多。在26°C NT下生长的“ Swifty Rosso”和在26或29°C NT下生长的“ Swifty Yellow”中，花朵呈枯萎状态。在26°C NT和26°C和29°C NT的'Swifty Yellow'中生长的'Swifty Rosso'中，异常花的百分比达到100％。在20或23°C NT下生长的植物中，花的大小最大，而在26和29°C NT下生长。净CO ₂ 在20或23°C NTs下生长的植物中，同化率的平均值很高。在26或29°C NTs下生长的植物中发现低的光合作用效率。在夏季，当NTs≥26°C时，DT较高，会延迟发芽并导致异常和枯萎的开花。由于它是一年四季的植物，因此可以有效地使用控制NT的技术，同时保持质量水平。