Relationship between the developmental stages of flower buds at the start of precooling and flowering in early forcing of tulip.

摘要

After harvest in mid-June, or 2 weeks after storage at room temperature, bulbs (11 cm in circumference) of tulips (Tulipa cv. Gander) were exposed to 34鳦 for 1 week, or 1 day with or without ethylene treatment at 10 or 50 鎙/litre air for 8 hours.After the exposure, bulbs were stored at 20?for 0-6 weeks, precooled for 3 weeks at 15?and were cooled for 8 weeks at 5鳦. Precooled bulbs were planted in a box and grown at 20/15?(day/night). When bulbs were pretreated with the high temperature and ethylene at the vegetative stage just after harvest, floral development was advanced and the resulting plants showed higher percentage flowering and earlier flowering. Length or weight of cut flowers and perianth length increased with extended storage period at 20? It is suggested that this is due to the bulbs being precooled at a more advanced stage of flower bud development. Cut flowers of good quality were obtained when bulbs were precooled from the outer perianth to gynoecium formation stages. However, the optimum stage differed with the duration of the high temperature exposure before the 20?storage, and differed due to whether or not the bulbs were given the ethylene treatment. The quality of cut flowers were determined best by the flower bud developmental stage when bulbs were moved to 5?after being stored at 15?for 3 weeks.