Characterisation of extracellular polysaccharides from suspension culturesof members of the Poaceae

Microscopic examination of suspension-cultured cells of Phleum pratense L., Panicum miliaceum L,, Phalaris aquatica L. and Oryza sativa L. showed that they were comprised of numerous root primordia. Polysaccharides secreted b y these suspension cultures contained glycosyl linkages consistent with the presence of high proportions of root mucilage-like polysaccharides, In con trast, suspension-cultured cells of Horedum vulgare L. contained mostly und ifferentiated cells more typical of plant cells in suspension culture. The polysaccharides secreted by H. vulgare cultures contained mostly linkages c onsistent with the presence of glucuronoarabinoxylan. The soluble polymers secreted by cell-suspension cultures of Phleum pratense contained 70% carbo hydrate, 14% protein and 6% inorganic material. The extracellular polysacch arides were separated into four fractions by anion-exchange chromatography using a gradient of imidazole-HCl at pH 7.0. From glycosyl-linkage analyses , five polysaccharides were identified: an arabinosylated xyloglucan (compr ising 20% of the total polysaccharide), a glucomannan (6%), a type-II arabi nogalactan (an arabinogalactan-protein; 7%), an acidic xylan (3%); and a ro ot-slime-like polysaccharide, which contained features of type-II arabinoga lactans and glucuronomannans (65%).