Modifications of cell wall polysaccharides during auxin-induced growth in azuki bean epicotyl segments
Nishitani K, Masuda Y
Plant Cell Physiol 21: 169-181
Changes in sugar compositions and the distribution pattern of the molecular weight of cell wall polysaccharides during indole-3-acetic acid (IAA)-induced cell elongation were investigated. Differential extraction of the cell wall and gel permeation chromatography of wall polysaccharides indicated that galactans, polyuronides, xylans, glucans and cellulose were present in the azuki bean epicotyl cell wall.When segments were incubated in the absence of sucrose, IAA enhanced the degradation of galactans in both the pectin and hemicellulose fractions, whereas to some extentit enhanced the polymerization of xylans and glucans in the hemicellulose fraction and an increase in the amounts of polyuronides in the pectin fraction and of α-cellulose. In the presence of 50 mM sucrose, IAA caused large increases in the amounts of all the wall polysaccharides, and enhanced the polymerization of galactans, xylans and glucans in the hemicellulose fraction.These results and an important role of galactan turnover in cell wall extension are discussed.Key words: Azuki bean epicotyl Cell extension Cell wall polysaccharides Galactans Indole-3-acetic acid.