OBSERVATION ON THE SECRETION ACTIVITIES OF CULTURED AND NON-CULTURED CELLS OF MANTLE TISSUE OF ANODONTA WOODIANA ELLIPTICA WITH SCANNING ELECTRON MICROSCOPE

By using scanning electron microscope and phase contrast microscope,the authors have studied the secretion by the cultured and non-cultur cells of the pallial tissue in Anodonta woodiana elliptica,and observed that both kinds of cells have very vigorous secretion activities.The cultured cells show merocrine and apocrine secretion.There are three modes of secretion:1.The secretory end forms a bulge wraped by a membrane.The bulges stretch gradually, and then their bases turn into narrow tubes,which finally separate from the cells and become secretory vesicles(merocrine).2.Long footlike structure begins to grow at the end of the cells,pushs the secretory substances into a distance and secretes them.Afterwards,the footlike structure shrinks into its original form.3.Many narrow branches are formed at the secretory end,and the secretory substances are secreted out of the branches-like fluid(apocrine secretion).When the rim zone of chromogenesis tissue of pallial layer is cultured,dark brown conchiolin-like crystals are similar to the sustances on the outermost layer of the shell, formed in the tissue piece and on the cells;When the exocuticle tissue piece without rim zone of chromogenesis is cultured,white or pale-yellow pearl-like crystals(similar to the substances on the inner-most layer of the shell)are produced.These results show that,if cultured under proper conditions,the cells may pnoduce the secretory substances having the same property as the substances produced in vivo.It is thus feasible to obtain the cell products by mass culturing cells.