ULTRASTRUCTURE OF VEGETATIVE ORGANIZATION AND CELL-DIVISION IN GLAUCOSPHAERA-VACUOLATA KORSHIKOV (PORPHYRIDIALES, RHODOPHYTA)

The ultrastructure of vegetative cells and cell division has been examined in Glaucosphaera vacuolata Korshikov. Features either not found or not denoted before include apparent intercisternal fusions within each Golgi body and fibrillar tracts possibly utilized by Golgi vesicles. Mitosis is closed except for large polar gaps and a spherical, presumptive MTOC (microtubule organizing centre) is present at prophase. The MTOC Battens by metaphase to fill the polar gap, becoming the focus of spindle microtubules. No NAO (nucleus associated organelle) was observed. All aspects of mitosis except the absence of an NAO are consistent with mitosis in red algae; most are not consistent with members of the Glaucophyta. Characteristics of mitosis and vegetative features, both those newly observed and those confirmed (especially the presence of connections between chloroplast lobes), support the removal of G. vacuolata from the Glaucophyta and its placement in the Rhodophyta. Also noted in this investigation were potential pyrenoid regions of the chloroplast and large complex bodies in the cytoplasm of dividing and non-dividing cells. The latter structures appear to be polycomplexes (polymerized units of the synaptonemal complex).