Changes in cell wall constituents during the cell cycle in a synchronous culture of Catharanthus roseus

Changes in cell wall constituents during the cell cycle were investigated using a synchronous culture of Catharanthus roseus (L.) G. Don which was obtained by the double phosphate starvation method (S. Amino et al. 1983. Physiol. Plant. 59: 393–396). Cell walls isolated from the cells in each phase of the cell cycle were fractionated into EDTA‐soluble (pectin), 5 and 24% KOH‐soluble (hemicellulose) and 24% KOH‐insoluble (cellulose) fractions. Their sugar compositions were investigated by gas chromatography and methylation analysis. The following changes were observed: (1) a significant increase in total cell walls in the G1 phase after cell division, (2) a temporary increase in the relative amount of the EDTA‐soluble fraction during cytokinesis, (3) an increase in the relative amount of galactose, probably 4‐linked galactose, in the EDTA‐soluble fraction prior to cytokinesis, (4) a temporary increase in the relative amount of 3‐linked glucose during cytokinesis, (5) little change in the composition of polysaccharides throughout the cell cycle in the 24% KOH‐soluble fraction, which consisted mainly of xyloglucan. The changes observed are discussed in relation to the progression and physiological significance of each phase of the cell cycle.