Studies Of Acarocidal Activity And Mechanism Of Thymus Mongolicus Against Fusarium Oxysporum

A plant. Thymus mongolicus. widely distributed in World, was investigated for its biological activity against Fusarium oxysporum, crude extract extracted by respective immersion, was separated by liquid-liquid distribution and purified through column chromatograghy, and its active constitute, L3, was separated. Its activities to active methods and inhibitory mechanism were studied. The results indicated:1. Thyme powder extracted by chloroform, methanol, petroleum ether, the extraction rate of the highest ethanol, chloroform, and the lowest was petroleum ether. Simultaneous determination of different extracts on Fusarium biological activity, the results showed that:thyme ethanol and petroleum ether matter crude extract in72h and48h to test bacteria spore germination and mycelial growth inhibition of crude extracts have a strong, the inhibitory effect of the chloroform extract of thyme poor. Concentration was2mg.ml-1, inhibition rate of mycelium and spore germination inhibition rate of ethanol extracts were75.98%and95.70%. When mycelial growth72h MIC was0.82mg.ml-1,48h MIC for spore germination was0.43mg.ml-1. Therefore, the ethanol extract of thyme chosen for further separation.2. The results of four different ethanol extract of thyme extract showed:chloroform extraction was(29.00%), methanol was (15.75%), ethyl acetate was(12.12%), petroleum ether was(10.30%). On the biological activity of extracts tracking tests showed that petroleum ether extract against mycelium growth and spore germination inhibition were the highest,81.2%and93.82%. after72h later, the MIC against mycelial growth was0.71mg.ml-1,48h later, the MIC against spore germination was0.45mg.ml-1.3. The petroleum ether extract was purified by column chromatography and thin layer chromatography detection, merging the same fractions obtained13fractions, The bioassay showed that the third fraction have strong antifungal activities, after72h of which to the inhibition rate mycelia growth was92.49%.4. Mycelium was processed by L3, A large number of Mycelium fracture Thickening decrease We can watch the chanhe by electron microscope,hyphae deformation, thickening; mycelial dry flat, shrinkage, Perhaps it impact on the formation of cell membrane and cell wall.5. By the L3processing Fusarium hyphae, cell membrane permeability was found in the determination, L3increases the mycelium cell membrane permeability, resulting in electrolyte leakage; determination of ergosterol content of the cell membrane, L3significantly inhibit its synthesis, indicating L3sites of action exists in the cell membrane of pathogens. While on the cell wall chitinase, assay L3found in2mg.ml-1,3h later,on the highest chitinase activity, hindered participation in the cell wall formation.After irrigating of cucumber seedlings, seedlings of SOD, CAT and POD activity also increased, indicating that the ethanol extract of thyme can induce SOD, CAT and POD activity increased, effectively improve the disease resistance of cucumber seedlings.6. In pot experiments,4mg.ml-1ethanol extracts of Fusarium protection and treatment of diseases of70.11%and68.64%. According to the test results, thyme extract has good antibacterial activity, there is a very good development prospects.