Mitosis and Cytokinesis in Haploid Plants of Rhizoclonium hieroglyphicum ssp. hieroglyphicum(Cladophoraceae, Chlorophyta).

Abstract

Mitosis and cytokinesis in haploid cells of Rhizoclonium hieroglyphicum ssp. hieroglyphicum were studied as the light microscope level.Nine stages of mitosis were distinguished: interphase, prophase, early and late metaphase, early, middle and late anaphase, and early and late telophase. Cells normally contained two interphasic nuclei. The onset of mitosis was synchronous in all the nuclei of any one cell and was sometimes found to be simultaneous in contiguous cells.The nuclear envelope disorganized at metaphase; during early metaphase twenty-four (6sm and 18m) homogeneously stained chromsomes formed a very dense circular arrangement.In anaphase, axis of the spindle usually formed an angle of about 30° with longitudinal axis of the cell. There was no great spindle elongation and the daughter nuclei remained close together. The nuclear membrane reorganized at telophase. Cytokinesis occurred by centripetal growth of a transversal wall.