Development of Ovule and Embryo Sac of Cocos Nucifera

Abstract

1. The axis of the flower must have developed long before the emergence of the inflorescence from the outer spathe, and develops the ovules after it has escaped from the spathe. The development of the embryo sac continues and proceeds up to about the receptive stage of the stigma. 2. The ovules are cauline, arising from the central axis of the flower. The floral axis bulges out, and papillae which serve as the nucellus of the nascent ovules are pushed toward each loculus of the ovary. The inner and outer integuments develop in succession. 3. The archesporium is one-celled, which does not cut off any parietal cell, but functions directly as the megaspore mother cell, which develops the embryo sac. 4. The megaspore mother cell divides in the usual manner, and produces the octonucleate sac, hence upon maturity we have the egg, two synergids, two polar nuclei, and three antipodals. 5. The polar nuclei fuse just after the opening of the inflorescence and before the degeneration of the antipodals and synergids. The polar nuclei migrate toward the center of the sac, where they fuse. 6. The synergids begin to disappear just before the time when the ovary becomes receptive.