| Plant diseases caused by Fusarium spp.seriously affect the yield and quality of crops.At present,chemical fungicides are the main controlling method.However,this solution was often accompanied with pathogen resistance,excessive residues of harmful chemical fungicides and even causing environmental pollution.Essential oil is expected to be a natural substitute for the chemical fungicides,while it can not directly be used in the practice.This is because essential oil is insoluble in water,volatile and not easy to be stored and transported.In this paper,Cirmamonun camphora chvar.Borneol leaves were used as raw material for the separation of essential oil as they are rich in essential oil.Solvent-free microwave-assisted extraction(SFME)was used as a substitute to the traditional hydrodistillation(HD)method.The antifungal activity of C.camphora chvar.Borneol leaf oil was evaluated on the inhibition of Fusarium spp.Ultrasonic assisted encapsulation method was developed to prepared essential oil microcapsules for further improving the utilization value of C.camphora chvar.Borneol leaf oil.The main contents and results are as following:1.SFME was employed to extract of C.camphora chvar.Borneol essential oil(CCBEO)and compared with HD.The optimal extraction conditions were obtained as follows: 65% of moisture content,30 min of microwave time,450 W of microwave power,and the actual yield of CCBEO was 42.03 ± 1.56 mg/g.The results of mass transfer kinetic models of the two extraction methods showed that the kinetic parameters of SFME were significantly higher than that of HD,and SFME just needed shorter extraction time to reach to the extraction equilibrium point in comparasion to that of HD.GC-MS was applied to analyze the composition of CCBEO.The results showed that the CCBEOs extracted by the two methods were similar,but the content of the main component(endo-borneol)extracted by SFME(80.08%)was much higher than that by HD(72.01%).The effects of the two methods on the environment were investigated and the results showed that SFME had the advantages of high efficiency,energy saving and environmental protection.2.The antifungal activities of CCBEO against Fusarium culmorum,Fusarium solani,Fusarium trichothecioides,Fusarium sporotrioides and Fusarium avenaceum were evaluated.The results showed that CCBEO has obvious antifungal activity against five Fusarium spp.,and the minimum inhibitory concentrations(MIC)all were lower than 2.00 mg/m L.Particularly,the antifungal activity on F.culmorum was the most significant and because its MIC was 1.00 mg/m L.The ultrastructure of the mycelial of Fusarium spp.treated with CCBEO,nystatin and without treatment were observed by scanning electron microscope(SEM).It was found that the mycelial ultrastructure showed obvious atrophy,collapse and even distortion after treatment with CCBEO.The results indicated that the CCBEO exhibited remarkable antifungal activity and has promising prospect to control the plant diseases caused by Fusarium spp.3.Ultrasonic assisted molecular inclusion was developed to prepare the CCBEO microcapsules and β-cyclodextrin was used as the wall material.The preparation conditions of microcapsules were obtained by single factor experiment as follows: 1:4of the core wall ratio,60 min of the ultrasonic time,350 W of the ultrasonic power and 50 ℃ of the embedding temperature.The yield and encapsulation efficiency of CCBEO microcapsules were 84.93 ± 2.21% and 60.20 ± 1.56% under the experimental conditions.The physical and chemical properties of the CCBEO microcapsules were characterized.It was found that the prepared CCBEO microcapsules was regular and their size were uniform.The process of microencapsulation obviously improved the thermal stability and release ability of CCBEO. |
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