Characterization of root hair cell walls as potential barriers to the infection of plants by rhizobia : the carbohydrate component.

The sugar compositions of root hairs of a variety of plant species were determined. Root hairs of legumes had very similar compositions, whereas those of different families varied widely. Only approximately 50% of the weight of the root hairs of legumes could be accounted for by sugar. Up to 80% of the weight of root hairs from other sources could be accounted for by sugars. Protein made up 5 to 8% of the weight of root hairs of dicots but only 1.3% in corn. Comparison between cell walls from various root cell types within legumes showed that the polysaccharide compositions of root epidermal, root hair, and root cortical cells were very similar. Cotton root hairs were markedly different from walls of mesophyll and epidermal cells of cotyledons from cotton.