Embryology of withania somnifera (L.) Dunal (Solanaceae)

摘要

We studied the embryology of Withania somnifera (L.) Dunal by light microscopy in order to reveal specific embryological features of the genus, and compared the results with embryological data on other members of the family Solanaceae. The key embryological characters of W. somnifera include dicotyledonous-type anther wall formation, simultaneous cytokinesis in pollen mother cells, binucleate tapetal cells, 2-celled mature pollen, anatropous, tenuinucellate and unitegmic ovules, polygonum-type embryo sac formation, the presence of an endothelium, and cellular endosperm formation. We give the first report of the dicotyledonous mode of anther wall formation (previously described as basic type) for the species. Comparative study suggests that anther wall formation, number of nuclei in tapetal cells, number of cells in mature pollen, mode of embryo sac formation and endosperm development are the most variable embryological features in Solanaceae. Some of these embryological features of W. somnifera should be of value for comparative study of related species and their phylogenetic relationships within the family.