Fig 6. Diagrammatic representation of different cell reproductive patterns found in Pseudokirchneriella subcapitata.

Three cell reproductive types were observed: a two-autospore type (b0-b2); a four-autospore type (c0-c2) (most frequently observed in the population in the 72 h after the start of culture), in which cytokinesis occurs by repeated binary fission after two nuclear divisions; and an eight-autospore type (d0-d2), in which autospore formation begins with separation of the cytoplasm into eight compartments, not by repeated binary fission as in the four-autospore type. The giant nucleus—type cell may also proceed to eight-autospore formation after multinucleation by three nuclear divisions. (c2) and (d2) also may occur as part of eight-autospore formation when the cell cycle restarts without the release of autospores.