FLORAL DEVELOPMENT OF HOPEA ODORATA

Abstract

Floral development of Hopea odorata Roxb. was carried out from mid December 1995 to late January 1996. The investigation started from flower initiation to fertilization. An individual flower H. odorata was a perfect flower composed of calyx, corolla, androecium and gymnoecium. During the early stage of development, stamens initiated from a central primordium of the young flower and formed anthers and filaments. In the late stage, the sporogenous cells developed into pollen grains. The pistil was formed from central meristem at the same time as the anther formed. It consisted of a stigma, a style and an ovary. There were six anatropous ovules superposed in three locules. At the anthesis, the megaspore mother cells produced a linear tetrad megaspore. One of four megaspores was functioned and formed the embryo sac with 8 nuclei. There were egg apparatus, two polar nuclei and three antipodal. The complete development process from the flower initiation up to the fertilization took about 40 - 45 days. After fertilization, the egg developed to be the zygote and differentiated into the “T” shape embryo in the ovule.