Research On Biological Activities Of The Extracts From 101 Kinds Of Plants Against Two Kinds Of Plant Pathogens

In this dissertation, studies were focused on finding natural bio-active from the abundant resources of plants. It is one of the hot spots to isolate these compounds and to make use of them as new agrochemicals or leading structure now.There are abundant resources of plants in North China, which can be used in clinical medicine, but rarely used in agriculture as fungicides. 46 families and 101 kinds of plants were selected. The acetone extracts and ethanol extracts were tested for the antifungal activities on Valsa mali Miyabe et Yamada and Rhizoctonia solani Kuhn. Morus alba L. was primarily studied, which provides the basis for the new style of botanical fungicide. And it is a great significance for the prevention and treatment of fungal diseases of crops and the sustainable development of agriculture. The results are as follows:Of the 101 kinds of acetone extracts, the inhibition rate of Sophora flavescens Ait. , Morus alba L., Stellera chamaejasme Linn., Agastache rugosa (Fisch. et Mey.) O. Ktze., Blechnum orientale Linn., Paeonia lactiflora Pall reached 80% or more for Valsa mali Miyabe et Yamada. The inhibition rate of Carpesium abrotanoides Linn., Inula helenium L., Agastache rugosa (Fisch. et Mey.) O. Ktze., Stachys sieboldii Miq., Ajuga lupulina Maxim., Sophora flavescens Ait., Semen dolichoris Album, Polygonum cuspidatum Sieb. et Zucc., Stellera chamaejasme Linn., Swertia diluta (Turcz.) Benth.et Hook. F., Blechnum orientale Linn., Kadsura heteroclita (Roxb.) Craib, Duchesnea indica (Andr.) Focke reached 90% or more for Rhizoctonia solani Kuhn. Of the 101 kinds of ethanol extracts, the inhibition rate of Carpesium abrotanoides Linn., Sophora flavescens Ait., Morus alba L. reached 80% or more for Valsa mali Miyabe et Yamada. The inhibition of Inula helenium L., Sophora flavescens Ait.and Morus alba L. reached 85% or more.Morus alba L. was selected for a further study of antifungal activity. Methanol extracts were continuously extracted by petroleum ether, ethyl acetate and n-butyl alcohol. At the concentration of 10mg/ml, the ethyl acetate extract has the highest activities to Valsa mali Miyabe et Yamada and Rhizoctonia solani Kuhn., and the growth inhibition ratios were 96.05% and 97.29%, respectively The petroleum ether extract has the good activities to Valsa mali Miyabe et Yamada and Rhizoctonia solani Kuhn. with the inhibition 80.05% and 81.12%, respectively.The ethyl acetate extract was isolated by the method of column chromatography. The results showed that L11, L14, L17, L20 have the highest activities to Valsa mali Miyabe et Yamada and Rhizoctonia solani Kuhn and the inhibition is 70% or more. Other extracts have lower activities. At the concentration of 10 mg/ml, the inhibition of L20 is 85.58% for Valsa mali Miyabe et Yamada and the inhibition of L20 is 90.12%. The inhibition of L17 is 78.38% for Valsa mali Miyabe et Yamada and the inhibition of L17 is 74.07%. By means of TLC and column chromatography, L20 was isolated. The results showed that L20-2 had the highest activities and the active ingredient may be a mixture of phenols, ketones and benzoic acid esters by means of GC-MS.