Abstract: The distribution characteristic and content change law of rhubarb polysaccharides in root of Rheum palmatum L. were studied by histochemical method and phenol-vitriol colorimetry. The results showed that the distribution of rhubarb polysaccharides in root was of multi-locus, rhubarb polysaccharides of root differently existed in phelloderm of periderm and parenchyma of secondary vascular tissue, the xylem parenchyma of secondary xylem and the phloem parenchyma of secondary phloem in root were the main tissues which stored and accumulated rhubarb polysaccharides. During different growth periods of root, the total content of rhubarb polysaccharides in the root and its tissues gradually increased with the growth of the plant but decreased slightly in a later period. Rhubarb polysaccharides content was greater in phloem parenchyma than in xylem parenchyma, the mode of rhubarb polysaccharide production was gradual storage and accumulation.

Key words: Rheum palmatum L., root, rhubarb polysaccharides, accumulation and distribution laws