Mitosis and cytokinesis in androgonidia ofVolvox carteri f.weismannia |
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Authors: | Regina Birchem G. Kochert |
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Affiliation: | (1) Department of Botany, Plant Sciences Building, University of Georgia, 30602 Athens, GA, USA |
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Abstract: | Summary Reproductive cells (androgonidia) ofVolvox carteri f.weismannia divide to form packets of 64 or 128 sperm cells. The androgonidium morphology, stages of mitosis, and cytokinesis were examined by electron microscopy. The biflagellate androgonidium loses its flagella before mitosis but the flagellar bases at the anterior end of the cell are retained. Two additional basal bodies are formed and the nucleus migrates from its central position to the area of the basal bodies before mitosis begins. A five-layered kinetochore is present on the chromosomes and remnant nucleolar material persists during mitosis. A furrow at the chloroplast end of the cell and the formation of phycoplast microtubules and vesicles signal the beginning of cytokinesis at early telophase. The cells maintain cytoplasmic connections until after the packet of sperm cells completes its development. |
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Keywords: | Cytokinesis Kinetochore Mitosis Sperm cells Volvox |
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