菊花光週反應與花芽分化組織解剖之觀察

An Anatomical Study on the Flower Bud Differentiaion in Response to Photoperiod in Chrysanthemum morifolium

將菊花四品種分置在自然對照（在實驗進行期間為12:40小時至13:40小時）與天黑後另加1、2、3小時人工照光下，以研究各種光照時數對其花芽分化與發育之影響結果簡述如下：（1）自春至夏，光照時數若超過14小時，雖有花芽分化，但其過程進展很慢。（2）光照時數超過14小時，中晚生種（13、15週）之花芽雖有花芽花化，但無小花繼續發育；即發育需更短之光照時數。（3）品種部差異皆經仔細調查。凡開花期愈晚之品種（13、15週），其花芽分化及發育；隨氣溫之昇高，需更短之光照時數。（4）中晚生種在秋冬季自然短日低溫季節，很容易花芽分化，發育而開花；而春夏季則否。在春及早夏季節，早生種祇需自然放任而不必人工照光即可開花。

Plants of four varieties of chrysanthemums were grown under natural daylength (12:40 to 13:40 hours during the time of the experiment), and supplementary artificial lighting after dark of 1 hour, 2 hours and 3 hours to determine the influence of photoperiod on flower bud initiation and development. Briefly stated, the results were as follows: (1) From spring to summer, though photoperiods over 14 hours duration did causeflower bud initiation, yet the process progressed very slowly. (2) Under photoperiods of over 14 hours duration, flower bud initiation occurred in the longer response varieties (13 weeks, 15 weeks), but no development of florets followed, This means that an even shorter photoperiod was needed for flower bud development. (3) Varietal differences were carefully noted. As the temperature rose, the later a variety flowered (13 week 15 week response varieties), the shorter was the photoperiod necessary for both initiation and development of flower buds. (4) For the longer response varieties, flower buds initated and developed to flowering very easily in fall and winter when the daylength was short and the temperature was low; whereas they did not flower in spring and summer. On the contrary, in spring and early summer, the shorter response varieties (9 weeks, 11 weeks) could flower under natural daylength without supplementary lighting.