ULTRASTRUCTURAL DIFFERENTIATION OF THE OVARIAN TRANSMITTING TISSUE INLILIUM-REGALE

The cells of the ovarian transmitting tissue of Lilium regale are papi lla shaped and form an epithelium on the placenta. Their ultrastructur al organization and differentiation from 1 d before to 7 d after anthe sis is presented. These placenta cells are typical transfer cells with a prominent secretion zone similar to that known from stylar canal ce lls. After anthesis the secretion zone continues to grow by addition o f vesicles from the numerous dictyosomes. Maximum depth of this zone i s reached by day 4 after anthesis. The outer surface of the cell wall is distinctly rugged on cell maturation and the outermost layer is cor roded. The ER system undergoes transition from a smooth to a granular condition. Before anthesis there is a central vacuole which at anthesi s is reduced to a system of small vacuoles. These are supplemented by autophagic vacuoles formed from the ER. Such vacuoles are found near t he secretion zone and may also fuse with the plasmalemma. The cuticle is sloughed and secretion commences before anthesis. Accumulations of vesicles found in the nucleus and occasional connections between such vesicles and the inner membrane of the nuclear envelope indicate the p resence of a nuclear network. Protein crystals are present in the cyto plasm and the nucleus. The starch grains in the plastids are digested after anthesis, but new ones are formed by days 6 and 7.