Relative distributions of phenol dimers and hydroxy acids in a cultivated soil and above ground maize tissue

The distributions of lignin-derived phenol dimers and cutin/suberin-derived hydroxy carboxylic acids were studied in a single analysis using CuO oxidation of maize leaves and stems as well as the plough layer of a silty soil cultivated with maize. Their relative contributions in soils and plants were compared to that of lignin monomers reported in a previous study. The x,16-dihydroxyhexadecanoic acid isomers and 9,10,18-trihydroxyoctadecanoic acid were the most abundant hydroxy acids in the soil. An x-hydroxy hexadecane-1,16-dioic acid was relatively enriched in soil compared to maize leaves. Hydroxy acids were relatively enriched in soils compared to lignin-derived phenols. Lignin dimers were relatively enriched in soil with regard to lignin monomers. Lignin dimers with 5,5 aryl–aryl and α,2-methyl linkages were the most concentrated dimers in soil compared to the plant tissue.