地锦提取液防治黄瓜白粉病效果及其抑菌物质的初步研究

测试了地锦提取液对黄瓜白粉病菌的抑制活性，并对地锦抑菌活性物质进行了初步的分离纯化。结果表明：地锦粗提液对苗期黄瓜白粉病有明显的预防效果，且防效随着粗提液浓度的增大而增加，浓度为30mg·mL^-1时，防效达到了67．45％；地锦中的抑菌生物活性物质为强水溶性，不易溶于石油醚、乙酸乙脂、正丁醇等有机溶剂；通过碱沉淀可以把大部分杂质从水相萃取物中沉淀下来，得到含有生物活性成分更高的上清溶液；LC—MS分析结果显示上清液中含有3种物质，推测它们的分子量分别为506、202和275。

Control Effect on Cucumber Powdery Mildew and Antifungal Compounds of Euphorbia humifusa Willd

Extracts of Euphorbia humifusa Willd were bioassayed to determine their protective effect against cucumber powdery mildew fungus, Sphaerothecafuliginea in the cultural room condition. The results showed that the crude extract had a protective effect of 67.45% at a concentration of 30＇ mg＇mL-I. The isolation of the active compounds from the crude extract was conducted by solvent partition. The bioassays of these phases we got showed that the most active compounds were in the water phase,, not in the organic solvent phases. It was indicated that most impurities could be deposited by putting alkali into the water phase and the more pure and active compounds were in the supemate. The results of LC-MS demonstrated that there were three substances in the supemate, and it was inferred that their molecular weights were 506、202 and 275 respectively,