虎杖根提取物及分离组分对黄瓜白粉病的作用效果

在实验室内进行了虎杖（Polygonum cuspidatum Sieb.etZucc.）根提取物及其活性组分分离研究,并且对黄瓜白粉病进行了活性测定及温室小区试验。结果表明,无论提取率还是作用效果,乙醇较适合于做为虎杖根提取物的提取溶剂。虎杖根乙醇提取物和乙醚提取物对黄瓜白粉病的EC90值分别为537.85、35.38mg/L,而乙醚提取后残留物的活性很弱,说明乙醇提取物中具有杀菌作用的成分主要存在于乙醚提取物中。用pH梯度分离法对乙醚提取物进行分离,得到3个不同组分,其中以氢氧化钠分离得到的组分对黄瓜白粉病显示了极高的杀菌活性。在温室条件下虎杖乙醇提取物在800～1600mg/L下对黄瓜白粉病的防效相当或优于对照药剂三唑酮。

The Activity of Root Extracts and Isolative Components of Giant Knotweed against Cucumber Powdery Mildew

The root extracts and isolated components of giant knotweed (Polygonum cuspidatum Sieb. et Zucc.) were prepared in lab and their activity against cucumber powdery mildew (Erysiphe cichoracearum) were evaluated in greenhouse. The results showed that ethanol is the suitable solvent for the preparation of test samples while considering both extract ratio and fungicidal activity. The LC50 of root ethanol extract and subsequent ether extract are 537.85 and 35.38 mg/L respectively,but the residue after extracted by ether showed very weak activity,indicated that the active ingredients were contained in ether extract part. Three components of ether extract were acquired by pH gradient isolation method. The component isolated by 5% NaOH showed excellent protective activity. In green house trial the root ethanol extract showed equivalent activity with triadimefon when applied at the concentra-tion of 800 to 1600 mg/L.