夏秋ギク'岩の白扇'および秋ギク'神馬'の生殖成長期の温度が開花および花序形態に及ぼす影響(発育制御)  [in Japanese] Influence of Temperature during Reproductive Phase on Flowering and Floral Morphology in Summer-to-Autumn Flowering-Type 'Iwa-no-hakusen' and Autumn Flowering-Type 'Jinba' Chrysanthemum : Chrysanthemum morifolium Ramat.(Growth Regulation)  [in Japanese]

夏秋ギク'岩の白扇(および秋ギク'神馬'について,東北地域における気温変化により生じる開花時期や切り花品質の変動要因を検討した.長日処理後,自然日長下の温度勾配型温室を用い,外気温の変動に追随して推移する高温あるいは低温条件下で生育させた.各品種について異なる時期に2回試験を行い,それぞれを温室への搬入日により,'岩の白扇'では7月8日および8月10日搬入作期,'神馬'では9月22日および10月13日搬入作期とした.'岩の白扇'では,温度区間で到花日数に差が生じ,特に発蕾以降の高温による開花の遅延が認められた.また,7月8日搬入作期に比べて短日条件となった8月10日搬入作期では到花日数がより短くなった.一方,'神馬'では,9月22日搬入作期に比べて発蕾前の気温が低くなった10月13日搬入作期の到花日数が長くなり,両作期において低温区で開花が遅延した.'岩の白扇'では低温および短日条件により管状花率が高くなり,'神馬'では低温により小花数が減少した.以上より,東北地域において夏秋ギク'岩の白扇'では発蕾以降の気温変動により8月開花の作型で開花時期が不安定になり,秋ギク'神馬'では著しい低温条件が開花遅延を招くことが確認された.

Fluctuations of flowering time and cut flower quality due to meteorological changes in temperature in the Tohoku region were investigated in summer-to-autumn flowering-type 'Iwa-no-hakusen' and autumn flowering-type 'Jinba' chrysanthemum. After long day treatment, plants were grown under natural day length and high and low temperature conditions in a temperature gradient chamber (TGC), in which the air temperature followed the natural outside temperature fluctuation. The experiments were carried out twice in different seasons; the dates of transfer to TGC were 8 July and 10 August for 'Iwa-no-hakusen', and 22 September and 13 October for 'Jinba'. In 'Iwa-no-hakusen', the temperature greatly varied during transfer on 8 July, and the anthesis was delayed by the high temperature after flower budding. The days to anthesis in transfer on 10 August was decreased by the shorter photoperiod than that at transfer on 8 July. In 'Jinba', anthesis was delayed by low temperature in both experiments. The days to anthesis following transfer on 13 October were increased by the lower temperature before flower budding than that of transfer on 22 September. The percentages of disk florets in 'Iwa-no-hakusen' were increased by low temperature and short photoperiod, and the number of florets in 'Jinba' were decreased by low temperature. In conclusion, the fluctuation of August flowering time of 'Iwa-no-hakusen' is induced by fluctuation of temperature, and the low temperature induces the delay in autumn flowering-type 'Jinba' in the Tohoku region.