The localized incorporation of 3H-L-fucose into cell-wall polysaccharides of the cap and epidermis of corn roots

Abstract

When ³H-L-fucose is provided to corn roots, a large proportion of the radioactivity is recovered in the polysaccharides extracted from the cell wall. Hydrolysis of this material yields ³H-L-fucose as the sole radioactive product. Two metabolites, identified tentatively as L-fucose-1-phosphate and a nucleoside diphosphate derivative of L-fucose have been isolated from the ethanol soluble fractions of the roots and are possibly precursors of the polysaccharide. Autoradiographs of tissue sections indicate that the synthesis of polysaccharides containing L-fucose is confined largely to the root-cap and epidermis. The outer epidermal wall and root-cap slime are particularly radioactive and, therefore, likely to be relatively rich in fucose. By contrast the cell walls from more deeply lying tissues incorporate negligible amounts of the sugar.