<正>以霍山石斛试管苗为材料，研究硝酸镧稀土10～40 mg／L、水杨酸0.2～5.0 mg／L和L-赖氨酸0.5-12.5 mg／L对石斛多糖含量的影响，并对石斛多糖提取工艺进行探讨。结果表明：稀土镧和L-赖氨酸对石斛多糖含量具有极显著影响，水杨酸有显著影响，在各自浓度范围内提高石斛多糖含量最适浓度分别为20、2.5和0.2 mg／L，与对照相比多糖含量质量分数分别增加76.33％、77.11％和23.60％。正交试验表明石斛多糖提取工艺的最佳方案为：100 mL的石油醚+100 mL体积分数为80％的乙醇+40 mL的料液。各因素对霍山石斛多糖提取的影响大小顺序依次为：体积分数为80％乙醇量、石油醚量、料液量。

Through investigating the poplar canker disease in north of Jiangsu, four kinds of symptoms on the poplar canker disease, i. e. blister, small circinal blotch, hlack blotch and hark rot, were found. The big black blotch canker was the most serious one among these cankers. The study on the virulence of three pathogens of cankers to the poplar was carried out. The results showed that there were significant differences in virulence among different pathogens to different poplars. The virulenees of Cytospora ctzrysosperma to poplar NL895(Populus X euramericana cv) aud 1-72(P. euramericana cv. 1-72/58) was greater than that of Phomopsis macrospora and Fusicoccum aescali. The virulences of P. macrospora and F. aesculi to poplar NL895and I-72were similar, while the virulences of three pathogens to poplar 1-69(P. deltoides ev. I-69/55) were similar.