| Root rot disease is an important fungal disease caused by Fusarium in Sophora japonica Linn,which seriously affects the growth and greening effect.of Sophora japonica Linn.Trichoderma spp.,as a kind of widely used biological control fungi,can control fungal diseases effectively.In this paper,the biological characteristics of T.longibrachiatuma SMF2 and T.harzianum T39,as well as the effects of them and their metabolites on five Fusarium that caused root rot disease in Sophora japonica Linn were studied and compared,so as to lay a foundation for the utilization of Trichoderma spp.in the control of agricultural and forestry diseases.The results show:1.By studying the effects of growth conditions such as different medium,temperature,light,p H and carbon and nitrogen sources on Trichoderma spp.,the biological characteristics of T.longibrachiatuma SMF2 and T.harzianum T39 were significantly different:under the same conditions,the mycelium growth rate of SMF2 strain was fast,while the sporulation ability of T39 strain was strong.Temperature conditions had the greatest influence on mycelium growth and spore production,SMF2 adaptive medium had a wider range,and T39 had a stronger ability to adapt to temperature.2.To clarify the inhibitory activities and antifungal mechanism of two kinds of Trichoderma spp.against pathogens,confrontational inclubation and microscopic observation methods were used to explore the probable mechanism of SMF2 strain and T39 strain against five kinds of plant pathogens.The results of confrontational inclubation experiment showed that the two kinds of Trichoderma spp had different degrees of antagonism on five kinds of plant pathogens,and the days longer,the inhibition effect more significant,meanwhile,the antagonism coefficient were ranked as Ⅱ4d after inoculation.The inhibitory rates of SMF2 strain against plant pathogens of F.equiseti and F.decemcellulare were higher;while the inhibitory effect of T39 strain on the other three kinds were stronger.Analysis of antifungal mechanism of two kinds of Trichoderma showed that Trichoderma competed for nutrition and spaced with plant pathogens,and showed mycoparasitic behavior against plant pathogens.The mycoparasitic mechanism of SMF2 strain was mainly manifested as twine or invasion with Fusarium,whlie T39 strain not only has entanglement,but also can cause mycelium of Fusarium to be constricted.3.The mycelia growth method was uesd to make clear the inhibitory effect of two kinds of Trichoderma fermentation broth against five kinds of plant pathogens and the optimized fermentation conditions.Usd direct extraction method and step-by-step extraction method to test the inhibiting activities of the extracs.The results displayed that the two kinds of Trichoderma fermentation broth had different degrees of antagonism on five kinds of plant pathogens;the inhibitive effect on F oxysporum was best and the inhibition rate of SMF2 strain fermentation broth was higher.The optimized fermentation conditions of two kinds of Trichoderma was different:at the temperature of 25±1℃,as for SMF2 strain,liquid mdium was wheat bran and fermentation time for 5 days,while,as for T39 strain,liquid mdium was PD and fermentation time for 7 days.Under direct extraction method,the inhibition effect of different kinds of organic solvent had significant difference,the inhibition effect of butyl alcohol extracswas the best. |
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