Developmental changes in cell-wall ferulate and dehydrodiferulates in sugar beet

Sugar beet (Beta vulgaris L.) seedlings were radiolabelled with C-14-cinnamate applied to the leaves. Cell-wall phenolic esters were analysed by HPLC. Different phenolic distributions were found in root and shoot, with dehydrodiferulic acids relatively more prominent in the root. Radioactive dehydrodiferulic acids (but not total dehydrodiferulic acids) increased as a proportion of saponifiable phenolics with increasing time after radiolabelling. This might be due to ferulate cross-linking in the cell wall as cells matured; alternatively, incorporation of pre-formed dehydrodiferulates into the wall or ferulate turnover might be responsible. Ratios of different dehydrodiferulates changed in the root with increasing time after radiolabelling, indicating differential control of formation of different ferulate dimers. The proportion of radioactivity that was non-saponifiable increased with time, indicating increases in ether-linked phenolics. (C) 1999 Elsevier Science Ltd. All rights reserved.