GLYCOSIDIC LINKAGE ANALYSIS OF POLYSACCHARIDES FROM WHEAT (TRITICUM-AESTIVUM L CV MILLEWA) INTERNODE WALLS DURING MATURATION AND FOLLOWING TREATMENT WITH POLYSACCHARIDE HYDROLASES

An analysis of the linkages between monosaccharides in wall polysaccha rides from wheat (Triticum aestivum L. cv. Millewa) internodes sampled at various stage of maturation using the partially methylated alditol acetate procedure, revealed increases in the proportions of (1-->4)-l inked xylosyl and glucosyl residues, but decreases in arabinosyl, bran ched xylosyl, and (1-->3)-linked glucosyl residues. Following an enzym atic treatment (pepsin plus polysaccharide hydrolases) there was an in crease in the proportion of (1-->4)-linked xylosyl residues, and decre ases in branched xylosyl residues and in the ratio of (1-->3)-linked t o (1-->4)-linked glucosyl residues. The residue from wheat internodes that had been treated with polysaccharide hydrolases after extraction of Bjokman lignin and water-soluble material was enriched in (1-->4)-l inked xylosyl and (1-->4)-linked glucosyl residues and had an elevated content of (1-->5)-linked arabinosyl, branched xylosyl, and glucosyl residues relative to the unfractionated walls. These residues may be a ttached to lignin via alkali-stable linkages that survive during methy lation. In addition, the quantity of sugars in residues of enzyme-trea ted cell walls, especially (1-->4)-linked xylosyl linkages, revealed s ignificant increases with maturation of plants indicating increases of the resistance to enzymatic hydrolysis during the maturation of plant s.