Cytological investigations of Gonyaulax Catenella Whedon and Kofoid and Peridinium balticum (Levander) Lemmermann.




Tomas, Ronald Norbert

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Texas A&M University


The percentage increase in cell numbers, the percentage increase in chain formation, the mitotic index and the normalized rate of cell division indicate that Gonyaulax catenella can be cultured parasynchronously obtaining up to 25-30% synchrony at the beginning of the 12:12 hr photoperiod. Almost 50% of all cell divisions occur during the 6 hr period spanning the end of the dark period and the beginning of the light period. Mitosis and cytokinesis are described and illustrated for the first time in the mesocaryotic, catenate dinoflagellate G. catenella. A structure similar to the central body of G. tamarensis and Gesenerium monilatum (=Gonyaulax monilata) is situated intranuclearly between the arms of the U-shaped interphase nucleus, and is suggested to function in the segregation of daughter chromosomes. This body has the fine structure of a nucleolus, and it is suggested that the term central body be replaced by persistent nucleolus (=endosome). The time required for the completion of mitosis is 4-6 hr, while cytokinesis requires at least 2 hr. Cytokinesis begins during the mitotic cycle, and the plane of fission is perpendicular to the mitotic plane of division. Parental moieties are retained and shared by the daughter cells as either a new enterosinistral moiety or a postero-dextral moiety is synthesized by the dividing cell.


316 pgs.


Gonyaulax catenella, Peridinium balticum, dinoflagellates, phytoplankton, algae, cytology, cell morphology, cell organelles