Microstructural Observations and Cytochemical Studies on the Archegonial Development and Oogenesis of Marchantia polymorpha

The development of archegonium and oogenesis of the hepatica Marchantia polymorpha were studied using microscopical and cytochemical techniques.The archegonium developed from an initial cell,which formed an apical cell and a basal cell by a transverse division.The apical cell produced an inner primary cell by three oblique vertical divisions and a transverse division.The primary cell formed a central cell and a neck canal mother cell by a transverse division.The central cell formed an egg and a ventral canal cell and the neck canal mother cell finally produced four neck canal cells.Maturation of the archegonium was accompanied by obvious elongation of the neck and swelling of the venter.As the egg matured,the nucleus became more irregular.Numerous vesicles and deep stained granules occurred in the cytoplasm and abundant mucilaginous materials were present around the egg.Cytochemical investigations indicated that the mucilaginous materials may be polysaccharide and the deep stained granules may be lipid in chemical nature.The ventral canal cell degenerated gradually after it formed.The neck canal cell degenerated later than the ventral canal cell.Four neck canal cells were the common rule,but occasionally five neck canal cells or binucleate neck canal cells were observed.