• Arabinogalactan;
  • Cell culture;
  • Cell wall turnover;
  • Extra-cellular polysaccharides;
  • Vinca


Five-day-cultured cells of Vinca rosea suspension culture were labelled with D-[U-14C]glucose for 3 h and were then incubated in a medium containing unlabelled glucose for 24 h. Before and after chasing, extra-cellular polysaccharides (ECP) and the cell walls were isolated from the medium and cells, respectively. ECP and polysaccharides in the hemicellulose fraction of cell walls were fractionated into a fraction precipitated as copper salt and one not precipitated as copper salt, and the latter was further fractionated using cellulose-powder chromatography. From the results of analyses of the sugar composition and methylation analyses, components of polysaccharides contained in each fraction were deduced. In ECP, the percentage of radioactivity in the arabinogalactan fraction increased during chasing, while in the cell wall radioactivity in the fraction containing arabinogalactan decreased during chasing. These results confirm the view that arabinogalactan in the cell wall is degraded, and secreted into the medium as a part of ECP.