[Study on accumulation of polysaccharides and alcohol-soluble extracts contents of Dendrobium officinale leaves].

This paper revealed the accumulation regularity of polysaccharides and alcohol-soluble extracts contents of Dendrobium officinale leaves, which have provided basis for the development and utilization of the leaves. The polysaccharides and alcohol-soluble extracts contents of three D. officinale strains leaves collected in different growing periods were determined by phenol-sulfric acid method and hot-dip method respectively. The results showed that the content of polysaccharides in leaves was 4.45% -12.17%, and was about a quarter in stems. The alcohol-soluble extracts content in leaves was 7.45% - 29.34%, and was 1.5 times that of stems. The quality variation of polysaccharides in leaves was closely related to the phenophase. The leaves with lower level of metabolism in three stages: winter, early germination stage and deciduous period, which led to lower content of polysaccharides. The leaves at the vigorous growth stage with higher content of polysaccharides. The alcohol-soluble extracts were closely associated to the formation and germination of buds. The content of alcohol-soluble extracts peaked before sprout, and promoted the growth of new shoots.