Changes in Neutral Sugar Compositions of Cell Wall Polysaccharides during Redifferentiation of Cultured Carrot Cells and during Maturation of Soybean Seeds

Changes in the neutral sugar compositions of cell walls werestudied during regeneration of shoots and roots from culturedcarrot cells and during maturation of soybean seeds. There weremore arabinan and arabinose-rich acidic polysaccharides thangalactose-rich polysaccharides in the pectic fractions of thecell walls from cultured carrot cells and more galactan, arabinogalactanor both than the arabinose-rich polysaccharides in the samefractions from their mother tissue, i.e. root phloem tissue. The arabinose content of the cell walls decreased and the galactosecontent increased during root and shoot formation until galactoseexceeded arabinose in the cell walls of fully developed shootsand roots from cultured cells. The cell wall arabinose contentalso was higher than that of galactose in cotyledons and embryonicaxes of immature soybean seeds, and change in the neutral sugarcomposition of the cell wall during seed maturation was similarto that during the redifTerentiation of cultured carrot cells.During the very late stage of maturation, galactose in the cellwalls exceeded the content of arabinose. Results suggest that the redifferentiation of roots and shootsfrom cultured cells goes through a process of cell wall formationsimilar to that of embryogenesis or seed development in themother plants. Results also indicate that the predominant arabinanand arabinose-rich acidic polysaccharides have important functionsin cell walls during embryogenesis and in the eraly stages ofseed maturation and that galactan, arabinogalactan, or bothreplace these arabinose-rich polysaccharides after seed maturation. ²Present address: Department of Botany, the University of BritishColumbia, # 3529-6270 University Blvd.,Vancouver, B.C. V6T 2B1Canada (Received October 28, 1982; Accepted April 8, 1983)