Isolation and characterisation of cell wall polysaccharides from Picea abies L

Cell walls of spruce (Picea abies L. Karst) callus cells were fractionated by sequential extraction with various reagents to obtain pectic polysaccharides, hemicelluloses and cellulose. The preponderent polymers were rhamnogalacturonans substituted to various degrees, with side chains of arabinan, galactan and arabinogalactan which contained mainly terminal, 3- and 5-linked, and branched 2,5- and 3,5-linked arabinose, terminal, 3-, 4-, and 6-linked and branched 3,6- and 4,6-linked galactose. The slightly acidic pectin-like polysaccharides of the alkali-soluble fractions were associated with hemicelluloses, i.e. xyloglucan, acidic xylan, glucomannan and/or galactoglucomannan. The spruce cell wall consisted of 50% noncellulosic polysaccharides of which 6-7% was xyloglucan, 28% cellulose, 13% protein, and 5% ash for a total of 96% of the cell wall. The primary cell wall was composed of the same type of polysaccharides as that found in dicotyledons, although the proportions of these polymers were different and their structures may not be identical. Key words: polysaccharides, 3- and 5-links, 2,5-branches.