STRUCTURAL FEATURE OF LIGNIN IN CELL-WALLS OF NORMAL AND FAST-GROWINGPOPLAR (POPULUS-MAXIMOWICZII HENRY) - LINKAGE TYPES OF ALL-BOUND HYDROXYBENZOIC AND HYDROXYCINNAMIC ACIDS

Sample from fast-growing poplar (Populus maximowiczii Henry) trees whi ch were hybridized, then bred successively by grafting of the Fl, and milled wood lignin (MWL) and lignin-carbohydrate (LCC) fraction prepar ed by Bjorkman's procedure from fast-growing poplar wood, and those fr om corresponding normal poplar tree were hydrolyzed with alkaline unde r various conditions. The released hydroxybenzoic and hydroxycinnamic acids were identified and quantified using gas chromatography-mass spe ctrometry and gas chromatography, respectively, to view the linkage ty pes to lignin. In addition to P-hydroxybenzoic acid esterified to lign in, a significant amount of ether-linked P-hydroxybenzoic acid, trace amounts of both p-coumaric and ferulic acids with ester- and ether-for ms also were detected. The presence of significant quantities of both ester- and ether-linked vanillic acids and syringic acids linked to li gnin and their distribution in MWL and LCC suggest that they would be involved in the intra- and/or inter-molecular bridges between lignin m olecules through vanillic and/or syringic acids. It also was suggested that there would be guaiacylglycerol-beta-vanillin and -syringaldehyd e ethers reported by Nimz in both normal and fast-growing poplar wood cell walls, because they were released by alkali hydrolysis under a N- 2 atmosphere. There were no clear differences between the cell walls o f normal poplar and those of fast-growing poplar woods in the amounts of hydroxybenzoic acid and hydroxybenzaldehydes.