Some features of embryology Campanula alliariifolia Willd. (Campanulaceae)

Abstract

he paper presents the results of studying the structure of the male and female generative spheres of the campanula Campanula alliariifolia Willd. (family Campanulaceae). Plant material for studying the processes of development of micro- and megasporangium was collected on the banks of the Fiagdon River in the Kurtatinsky Gorge, as well as in the area of the city of  Gagra. It has been established that the type of formation of the microsporangium wall is centrifugal; the tapetum is the result of the development of the primary parietallayer. The formed wall of the microsporangium consists of the epidermis, endothecium, one, sometimes two middle layers and a secretory tapetum. The wall of a mature anther is represented by flattened cells of the epidermis and endothecium with fibrous thickenings. Tetrads of microspores are formed simultaneously. Mature pollen grains are 2-celled, 3-pore, 4-pore, and occasionally even 5-pore. The gynoecium is represented by many anatropic, unitegmal, medionucellate, funicular ovules. An  integumental tapetum develops, reaching the level of the apex of the egg and covering approximately ¾ of the embryo sac. As a result of meiosis, a linear tetrad of megaspores is formed, the chalazal of which develops into the embryo sac. The embryo sac is elongated, the micropyle is long, narrow and straight. A postament and podium are formed at the base of the embryo sac. A small number of anomalies in the development of male and female  elements suggests the possibility of the for-mation of full-fledged seeds.