CHANGES IN PHENOLIC-ACIDS FROM INTERNODE WALLS OF WHEAT AND PHALARIS DURING MATURATION

Quantitative changes in p-coumaric, ferulic and dehydrodiferulic acids in maturing internode walls of wheat (Triticum aestivum cv. Millewa) and phalaris (Phalaris aquatica cv. Sirosa) have been measured. The proportions of these cinnamic acids in ester linkages was 0. 1 6-1.5:1.0:0.03-0.15 for wheat and 0. 1 3-2.09:1.0:0.02-0.09 for phalaris. Significant amounts of dehydrodiferulic acid were released by alkaline digestion at 170-degrees with 4 M NaOH from walls of wheat and phalaris internodes (0.08-0.35% wt for wheat, 0.15-0.41% wt for phalaris). This was 10-20 times higher than the amount of esterified dehydrodiferulic acid. It is proposed that this dehydrodiferulic acid, in the form of diester bridges between polysaccharide chains, is also etherified to lignin.