[Objective] The aim of this study was to develop a simple and effective method for the polysaccharide extraction from Spirulina. [Method] The polysaccha- rides were directly extracted from the fresh algae mat or dry powder of Spirulina in boiling water. The contents and quality of the extracted polysaccharides were measured. [Result] On average, 236.06 g of polysaccharide was extracted from 25 kg of fresh Spirulina mat, with a yield rate of 0.94%, while 191.95 g of polysac- charide was extracted from 2.5 kg of dry powder of Spirulina with a yield rate of 0.77%. The polysaccharide content in the extract of fresh Spirulina mat was 12.56% （according to glucose content）, while that of the dry powder was 12.38% （according to glucose content）; the glucose was produced during the hydrolysis of Spirulina polysaccharide. [Conclusion] Extraction polysaccharide from Spirulina with boiling wa- ter greatly reduces the use of ethanol, and the possibility of pollution from the ex- ogenous non-food chemical reagents, so that the extracted polysaccharides can be used as food materials. This method makes it possible to establish the production line for Spirulina polysaccharide.
[Objective] In order to better meet the requirement of crops on a more and more accurate water content under various planting environment of modern agri-culture, an automatic test system of soil water characteristic curve was designed by combining the conceptions of soil moisture content and soil water potential. [Method] Electronic soil moisture tension meter was used to determine the real-time tension value of soil moisture in the tested container, and the electronic Weigh sensor was used to determine soil Weigh. Minusing method was used to calculate soil moisture content, based on which the soil water characteristic curve was plotted. [Result] Through the filed survey of 2 different kinds of soil in Jiangsu Province, the results were as fol ows： soil of different composition showed different trend in soil water characteristic curve that the soil water characteristic relation of the sandy soil in the old course of the Yel ow River in Xuzhou was Y=-0.000 2X3＋0.027 7X2-1.644 5X＋38.161, R2=0.991 9; while the soil water characteristic relation of the saline-alkali soil in Jinhai Farm of Dafeng was Y=-0.00 2X2-0.426X＋39.905, R2=0.991 3. [Con-clusion] The automatic test system of soil water characteristic curve soil water char-acteristics curve could reflect soil moisture content and soil water potential, as wel as reflect the effectiveness of soil water to plant growth, providing basis for the sci-entific irrigation.
