カキの成木結果樹を供試し, それぞれ樹体の発育周期に応じて, 夜間に補温処理を行ない, 枝梢の生長, 開花ならびに果実の肥大に及ぼす影響を調査した。その結果, 新梢伸長期(自然夜温12∿13.4℃)および果実発育の第1期(自然夜温21∿22℃)に3∿4℃以内で夜間補温すれば, 新梢の生長, 開花および果実の肥大を促進し, とくにその期間中で処理を打ち切った後もその影響が維持されて収穫期にまでおよぶ。しかし, この時期に自然夜温より6∿7℃以上の高夜温になると, 一時的には展葉, 開花ならびに幼果の肥大は促されるが, 枝葉は軟弱徒長し開花後の落果が著しい。開花と萠芽時よりの積算夜温とは密接な関係を示し, 4月始めよりほぼ470℃∿500℃で開花期に至る。Some effects of night temperature on the shoot elongation, blooming and enlargement of fruit were studied by Confining fruiting limls during the night (7p.m-7a.m) in heated chambers. By the treatment at the shoot growth stage (the mean natural night temperature is 12-13.4℃ through treatment period) and the first stage of fruit growing (the mean natural night temperature is 21-22℃ throught treatmentp eriod), shoot elongation, blooming and fruit enlargement were much acceler ated, in case of 3∿4℃ above the natural night temperature, and this tendency was continued till harvest, even if the treatment discontinued merely at the first stage of fruit growing. However, when the treatment tremperature was 6∿7℃ higher than the natural night temperature, all young fruits fell down at about 10∿20 days after the treatment. The flowering is closely connected with the accumlatively night temperature before the flowering. In the treatment of 1959 and 1960,we observed that accumlatively night temperature from the beginning of April to flowering stage is 470-500
