掌叶大黄根多糖的积累分布特征

采用组织化学方法和苯酚硫酸比色法研究了掌叶大黄（Rheum palmatum）根中大黄多糖的贮藏分布特征和含量变化规律。结果表明：大黄多糖在根内的贮藏是多位点的，在根周皮的栓内层、次生维管组织的薄壁细胞内不同程度地贮藏和积累了一定数量的大黄多糖，次生木质部的木薄壁细胞和次生韧皮部的韧皮薄壁细胞是主要贮藏和积累的部位；不同发育时期根中大黄多糖含量的变化规律为，随着植物的不断成熟，根及其各组织中大黄多糖的总含量表现为逐渐增高的趋势，但在发育的后期略有下降；韧皮薄壁细胞与木薄壁细胞相比，贮藏大黄多糖的含量相对较多，大黄多糖的贮藏积累方式为逐渐累积的方式。

Accumulation and Distribution Characteristics of Rhubarb Polysaccharides in Root of Rheum palmatum L.

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.