Cell- and colony-division in Eudorina (Chlorophyta: Volvocales) and some ecological implications

Abstract

The growth of Eudorina unicocca in laboratory culture is shown to conform to a model based upon the in situ formation of daughter colonies from the cells in mother colonies and upon their subsequent recruitment to the population. It is shown that this mode of growth enables the alga to maintain a rapid rate of increase (ca. 0·6 day^-1, equivalent to approx. 0·9 cell divisions day^-1) even though only 4% of the colonies divide each day. Net growth is possible even at high intensities of filter-feeding by zooplankton.