Lignin in young plants

Abstract

Alkali-extractable lignins ("alkali lignins") were prepared from, barley, from feces collected from sheep fed exclusively with barley, and from cotton seed hulls. The materials used for lignin extraction and the isolated lignins were subjected to hydrolysis with dilute acid, water at 210[degree] and alkali at 210[degree]. All treatments with acid, including the conventional lignin detn. methods, and treatment involving high temps., lead to extensive condensation reactions within the lignin molecule, through the aliphatic and aromatic hydroxyl groups. Treatment with dilute alkali leaves lignin comparatively unchanged, treatmant with stronger alkali and at temps. over 100[degree] leads to their gradual degradation. The N content of the lignins is not due to their contamination with protein. The lignins contained in the plants investigated are very similar, probably all containing the same phenylpropane basic structural unit. The structural details of the lignin molecule were discussed in the light of the results obtained.