Changes in glucan synthase activities during the cell cycle in a synchronous culture of Catharanthus roseus

Glucan synthase activities were determined during the cell cycle in a synchronous culture of Catharanthus roseus (L.) G. Don. Using radio gas chromatography, it was confirmed that glucans produced by a crude particulate extract from 1 μ M UDP-glucose were rich in 4-linked glucose residues, and that those formed from 1 m M UDP-glucose contained mostly 3-linkages. Glucan synthase activity with 1 m M UDP-glucose increased prior to cytokinesis. In the G1 phase after cell division, glucan synthase activities with both 1 μ M and 1 m M UDP-glucose were high, which may correlate with the maximal active synthesis of cell wall polysaccharides in this period of the cell cycle as reported by S. Amino et al. (Physiol. Plant. 60: 326–332, 1984).