FACTORS OF EQUATORIAL CONTRACTION AND POLAR MEMBRANE EXPANSION IN ENDOSPERM CYTOKINESIS

¹ Department of Zoology, Duke University, Durham, North Carolina

Divisions of living endosperm cells of Hemerocallis have been observed in hanging drop preparations where they are not distorted by flattening. Equatorial constriction and polar membrane expansions occur in late anaphase and appear quite comparable to corresponding stages of cytokinesis in animal cells. Failure of equatorial constriction, of polar membrane expansion, or of cell plate formation results in failure of cytokinesis. It is suggested that equatorial contraction and polar membrane expansion may be functionally important in the mechanism of cytokinesis of endosperm cells, as they are in animal cell cytokinesis.