© 1997 Heron Publishing—Victoria, Canada
Time and method of floral initiation and effect of paclobutrazol on flower and fruit development in Shorea stenoptera (Dipterocarpaceae)
Dida Syamsuwida (1) and John N. Owens (2)
1. Forest Tree Improvement Research and Development Institute, Jl. A.M. Sangaji Km. 15, Purwobinangun, Pakem, Sleman, DI Yogyakarta
55582, Indonesia / 2. Centre for Forest Biology, University of Victoria, Victoria, B.C. V8W 2Y2, Canada / Received January 11, 1996
Summary
Small Shorea stenoptera Burck. (Dipterocarpaceae) trees of reproductive age growing in an arboretum in west Java were studied to determine the pattern
of vegetative shoot development, the time and method of floral initiation and the effect of paclobutrazol on floral enhancement.
Vegetative buds were enclosed by two stipules between which was a leaf primordium, a small axillary vegetative bud and another
pair of stipules. This sequence was reiterated five to seven times before the vegetative apex was visible. At the time of
floral initiation, axillary buds developed into floral spikes and compound inflorescences formed at the end of drooping branches.
A compound inflorescence might bear many floral spikes and each floral spike bore many flowers. The compound inflorescence
was a modification of the reiterative developmental pattern observed in vegetative shoots. The time of floral initiation began
in late June or early July and continued until about November. Floral enhancement using paclobutrazol as a soil drench was
attempted in mid-July, but this was later found to be after the onset of floral initiation, and the treatment failed to enhance
flowering; however, it appeared to enhance the rate of floral and fruit development. The similarity in vegetative bud development
among dipterocarp genera suggests that the time of floral initiation may be easily determined in many species based on simple
dissection techniques.
Keywords:
dipterocarp, floral enhancement, shoot development.
