The study of development of generative organs in Calendula officinalis L.

Calendula officinalis is a perennial herb with bisexual and functionally female florets often used for medicinal purpose and ornamentation. The inflorescences is capitule and consists of fertile and solid sterile florets. Sterile florets consists of ray florets with decresed generation system. Fertile florets are divided to two groups of bisexual and female florets. In bisexual florets, the anther wall is composed of epidermis, endothecium, middle layer and tapetum. But the middle layer degenerates and only in primary levels distinguished. The tapetum is mainly secretive. For bisexual florets, cytokinesis is simultaneous and leads to tetrahedral tetrads. Bisexual florets are functionally male and solid. Also female florets have active ovules. Ovules are unitegumic, tenuinucellatae, anatropus. Before the differentiation of micropylar cells in to egg cell and synergids, two polar nuclei fuse and sntipos start degenerating. Development of embryo sac follows the monosporic, polygonum type.