Abstract
A light and transmission electron microscope study was made on the disposition of an egg cell and two synergids in Oryza sativa ovules. After anthesis, one of the synergids is rather persistent while the other is degenerating with collapse of the plasma membrane and penetration of ground plasma into the space between the plasma membranes of the egg cell and the central cell. Spherical vesicles in degenerating synergids closely resemble polysaccharide particles in intact pollen grains. Singular cisternae in the central cells tightly associate with the plasma membrane which borders on the degenerating synergids. There are osmiophilic deposits in the narrow interspace between the plasma membranes of the egg cell and the persistent synergid or the central cell. The egg cell has a nucleus with two nucleoli. The persistent synergid has a malformed nucleus forced on a pocket portion of central cell. The portion is occupied by a large number of cell wall ingrowths. It is postulated from the cyto-histological features of ovaries that nutrition into the egg cells is supplied through transmembranal, symplastic and apoplastic routes.
