| Purpose:Panax notoginseng is a plant with suitable for the dark and humid environment.Due to its special planting environment and huge demand,The artificial planting area increases sharply,which leads to its increasingly serious disease problems.P.notoginseng diseases mainly include the above-ground part and the underground part.At present,the prevention and treatment of these diseases mainly rely on chemical fungicides.Chemical control could prevent and cure diseases in some way,while it also brings many bad effects.Therefore,it is necessary to find a safe and effective new botanical fungicide method to improve the quality of P.notoginseng.In this study,Artemisia annua,Syzygium aromaticum were taken as research objects to study the inhibitory effect of crude extract and essential oils(EOs)on the pathogenic fungi causing P.notoginsen disease,which could provide some theoretical basis for ecological prevention and control of P.notoginseng Method:1.The effects of methanol crude extract from A.annua leaves on spore germination rate,spore activity,mycelial growth and spore production of Fusarium oxysporum were determined.2.The inhibitory effect of A.annua extracts with different polarity on P.notoginseng root.3.Plant EOs was extracted by steam distillation and the inhibitory effects on pathogenic fungi of P.notoginseng were detected.4.The main components and contents of EOs of plant were analyzed by GC-MS.5.The minimum inhibitory concentration of EOs and their main components were determined by 96-well plate method.6.Chessboard method was used to determine the inhibitory effect of EOs on pathogenic fungi after combining with hymexazol.Result:1.The crude methanol extract from A.annua leaves could reduce the spore germination rate and spore activity of F.oxysporum,inhibit the growth of mycelia and spore production.Then the inhibitory effect on F.oxysporum became stronger with the increase of the concentration of the crude methanol extract from A.annua leaves.2.The root,stem and leaf of A.annua were extracted with methanol.And the results showed that the inhibition effect of A.annua leaf on pathogenic fungi was the most significant.Then the A.annua leaf were extracted with solvents of different polarity and tested for fungi.It was found that the inhibition effect of A.annua leaf EO was the best.As can be seen from the results of vivo experiment,petroleum ether extract from A.annua within a certain concentration had some inhibitory effect on the incidence of P.notoginsen infected plants.3.The results of in vitro test showed that the EOs of S.aromaticum buds,S.aromaticum fruits had significant inhibitory effects on the growth of mycelia of the pathogenic fungi of P.notoginsen diseases.When the concentration of EOs was 50 mg/mL,and the inhibition rates of S.aromaticum buds EO on Pythium aphanidermatum,Botrytis cinerea,Colletotrichum gloeosporioides,and Rhizoctonia solani were 100.00%.The inhibition rates of S.aromaticum fruits EO on P.aphanidermatum and C.gloeosporioides were 100.00%.4.The GC-MS analysis were carried out on the EOs to determine their components and corresponding percentage.The highest content compound in S.aromaticum buds EO was eugenol with 57.95%,followed by eugenol acetate(16.49%)and caryophyllene(15.89%).Then the compounds with the highest content of S.aromaticum fruits EO were2',3',4'-trimethoxyacetophenone(50.45%)and eugenol(39.26%).5.The MIC results showed that EOs of S.aromaticum and their main components had significant inhibitory effects on the fungi,and MIC values were different for pathogens with different EOs and their monomers.The MIC values of eugenol and eugenol acetate against pathogens ranged from 0.04 ~ 0.42 mg/mL and 0.01~0.34 mg/mL.The MIC values of 2,3,4-trimethoxyacetophenone were 0.01 ~ 1.36 mg/mL.6.In order to further explore the synergistic effect of EOs with hymexazol,theantifungal activity was measured.The combination of S.aromaticum buds EO with hymexazol showed a synergistic effect on the inhibition of P.aphanidermatum,B.cinerea,and showed additive effect on the inhibition of Cylindrocarpon destructans.Then the combination of S.aromaticum fruits EO with hymexazol showed a synergistic effect on the inhibition of C.gloeosporioides,with additive effect on the inhibition of F.solani,P.aphanidermatum,and B.cinerea.7.The results of in vivo experiments showed that the MIC value of S.aromaticum buds EO could significantly reduce the incidence of grey mould of P.notoginseng and improve the control effect.Conclusion:The crude methanol extract from A.annua had certain inhibitory effect on F.oxysporum and F.solani,which could cause root rot of P.notoginsen.The results of in vivo experiments showed that when the concentration of petroleum ether extract from A.annua was 0.50mg/g,the incidence of P.notoginsen was only 25.00%,which was much lower than that of the control group by 42.22%.The results revealed that A.annua could prevent and cure root rot of P.notoginsen.The results of in vitro test showed that the EOs of S.aromaticum buds and fruits had significant inhibitory effects on the growth of mycelia of the pathogenic fungi of P.notoginsen diseases.The main components of S.aromaticum EOs were eugenol,eugenol acetate and 2,3,4-trimethoxyacetophenone by GC-MS analysis.The MIC vaules showed that the MIC range of eugenol was 0.04 ~ 0.42mg/mL,while the MIC of hymexazol against pathogenic fungi was 0.04 ~ 0.31 mg/mL,indicating that the antifugal effect of the major monomer compounds was similar to that of hymexazol.The EO of S.aromaticum buds in combination with hymexazol had a significant effect on the prevention and control of grey mould of P.notoginsen. |
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