Structural characteristics of oxalate-soluble polysaccharides from Norway spruce (Picea abies) foliage.

Structurally different polymers were derived from Picea abies foliage by successive extraction with water (PA), HCl solution (PA) and (NH)CO solution (PA). The P. abies foliage was found to contain basically low-methoxyl pectin extractable with an (NH)CO solution. PA was shown to comprise primarily arabinogalactan-proteins (AGPs); PA was composed of mixed AGPs and pectic polysaccharides, with the latter prevailing; and polysaccharide PA isolated in the highest yield included chiefly pectic polysaccharides. The major constituents of PA were low-methoxyl and low-acetylated 1,4-α-d-galacturonan and partially acetylated RG-I. The sugar side chains of RG-I contained chiefly highly branched 1,5-α-l-arabinan and arabinogalactan type I as a minor constituent. RG-I whose side chains had 1,5-α-l-arabinan represented short regions alternating with non-acetylated and unmethylesterified galacturonan regions. In addition to pectins, polysaccharide PA contained AGPs, xylanes and glucomannans, indicating that these polysaccharides are in an intimate interaction.