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International Journal on Algae
SJR: 0.219 SNIP: 0.261 CiteScore™: 0.24

ISSN Imprimir: 1521-9429
ISSN On-line: 1940-4328

International Journal on Algae

DOI: 10.1615/InterJAlgae.v3.i2.20
pages 18-30

A new type of cell division in Chlamydomonadaceae (Chlorophyta)*

N. P. Masyuk
N.G. Kholodny Institute of Botany, National Academy of Sciences of Ukraine, 2, Tereshchenkovskaya St., 01001 Kiev, Ukraine
E. N. Demchenko
Department of Botany, Taras Shevchenho National University, 64, Vladimirskaya St., 01017 Kiev

RESUMO

A new type of cell division found in plants for the first time in some species of Chlamydomonadaceae (Sphaerellopsis aulata (Pasch.) Gerloff and Chlamydomonas sp.) is described and named protocytotomy. The main peculiarity of protocytotomy is that prior to the division of the parental cell a new elastic cell wall appears under the old one which enlarges and then becomes slimy. The new internal wall divides together with protoplast, and forms the cell walls around the products of the division. The division occurs by way of farrow cleavage of the parental cell covered by the internal cell wall within the external one. Protocytotomy has common features with schizotomy of naked monads; however, it takes place in the cells covered by two cell walls. It also recalls cytotomy of multicellular algae but differs from the latter by taking place inside the external cell wall that does not participate in the cell division, and by being completed by separation of the division products. The new type of cell division described below was observed in representatives of the genera Chlamydomonas Ehr. and Sphaerellopsis Korsch. along with typical schizogony. Apparently, protocytotomy is quite common in chlamydomonads. The probable position and importance of protocytotomy in evolution of cell division in plants are discussed.