Zellteilung und Sporulation als wichtige Unterscheidungsmerkmale bei Grünalgen (Chlorophyta)

Abstract

Summary The cell division is an important character in the filamentous green algae, mainly in the unicellular forms where the cell division is the only modus of reproduction and where with they differ from the unicellular coccoid algae reproducing by sporulation. Sometimes it is difficult to distinguish between both processes if only two autospores in coccoid algae are produced. The cell division is a process where one cell divides into two equal parts (daughter cells) by mitosis and following cytokinesis. Both daughter cells using the mother cell wall grow up and divide again. In contrary the sporulation is a process where the cell mostly divides into few or many daughter protoplasts (precursors of spores), while the mother cell wall is forming the sporangium. In multicellular algae the cell division serves to the growing, development and differentiation of the multicellular organism, while the sporulation only to the reproduction. The cell division in green is sometimes algae also a modus of reproduction: As schizotomy (bipartition) in naked Phytomonadina and as cytotomy (vegetative cell division) in the unicellular algae of Stichococcus- or Closterium-type. With regard to the characters it will be relatively easy to distinguish between cell division and sporulation. Only an example where both terms were taken by mistake are pseudofilaments (Cylindrocapsa, Radiofilum) or diads and tetrads (Chlorosarcinales) with modified sporulations. A survey of all differences between cell division and sporulation is enclosed.