Accumulation and Distribution Characteristics of Rhubarb Polysaccharides in Root of Rheum palmatum L. The Localization Characteristics of Rhubarb Polysaccharide in Stems and Leaves of Rheum tanguticum Maxim.et Balf.var.liupanshanense Cheng et kao Studies on application of ultra-filtration to purifying polysaccharides
from Rhubarb