LIGNIN OF THE TEA PLANT AND CALLUS-CULTURES INITIATED FROM IT

Alkaline nitrobenzene oxidation and gas-liquid chromatography have bee n used to study composition of the products of lignin breakdown in lea ves and stems of the tea plant and in callus cultures initiated from l eaves and stems and grown under different conditions (light, darkness) . A guaiacyl-syringyl type of lignin is synthesized in tissues of the intact plant. Vanillin, syringic aldehyde, and syringic acid are the m ain products formed during nitrobenzene oxidation of lignin from leave s and stems of the tea plant. Leaf lignin has a higher degree of metho xylation. Culturing of tea tissues and their prolonged growth in the d ark lead to changes in composition of the lignin synthesized by them. The products of lignin breakdown in heterotrophic callus cultures are represented not only by guaiacyl and syringyl structures (vanillin, va nillic acid, syringic aldehyde, and syringic acid), but also by signif icant amounts of p-hydroxyphenyl structures (p-hydroxybenzaldehyde and p-hydroxybenzoic acid). It is concluded that in regard to type, the l ignin of heterotrophic callus cultures is a phylogenetically more prim itive lignin. In photomixotrophic callus cultures grown under light, a guaiacyl-syringyl type of lignin is synthesized that in its compositi on approaches the lignin of intact plant tissues.