Formation and Multiplication of Double Cells in a Green Alga, Micrasterias crux-melitensis (Ehrbg.) Hass

抄録

When kept at 4°C for 24h, growing cells of Micrasterias crux-melitensis lost their septa or cell walls which had separated the cells into two daughter cells, forming binucleate cells. These binucleate cells grew into double cells, each of which consisted of a middle section and two side sections. Five types of multiplication for the double cells were observed; two normal cells and a double cell were produced from a double cell in the first type; a normal cell, an anucleate cell and a double cell in the second type: two presumably anucleate cells and a double cell in the third type; an apparently normal cell and a triple cell in the forth type; and a quadri cell in the fifth type. These five types originated from different distributions of daughter nuclei in the daughter cells. When the middle section of a double cell was very small, no daughter half cells were formed from the middle section, though the middle section had two nuclei in it. The anucleate cell and the effect of the position of the nucleus upon the growth of daughter half cells are discussed.