Pea Xyloglucan and Cellulose : IV. Assembly of beta-Glucans by Pea Protoplasts

The synthesis and assembly of xyloglucan were examined during early stages of wall regeneration by protoplasts isolated from growing regions of etiolated peas. During early stages of cultivation, fluorescence microscopy showed that the protoplast surface bound Calcofluor and ammonium salt of 8-anilino-1-naphthalene sulfonic acid and, in time, it also bound fluorescent fucose-binding lectin. Based on chemical analysis, 1,3-beta-glucan was the main polysaccharide formed by protoplasts and xyloglucan and cellulose were minor wall components. Binding between cellulose and xyloglucan was not as strong as that in tissues of intact pea plants, i.e. mild alkali could dissolve most xyloglucan from the protoplast. However, the addition of exogenous pea xyloglucan into the culture medium stimulated the deposition of new polysaccharides into the protoplast wall and enhanced the close association of newly formed xyloglucan with cellulose.