| The effects of temperature,pH and nutriment on the mycelial growth,dry mycelium weight and thermal death point of their conidium of Trichothecium roseum from different hosts including cotton,grape,apple and melon were studied,and pathogenicity of conidium and mycelium of T.roseum to apple fruit was tested on condition of artificial inoculation in laboratory respectively.Moreover,the antagOnism to pathogenic fungus was analysed systematically for the first time and the cultural filtrate of the T.roseum in the liquid culture was regarded as the one of most inhibitor agent.The main results were as follows.1.The research of biological characteristics of T.roseum showed that the mycelium could grow at 10-35℃,with the optimum temperature being in the range of 15-30°.It couldn't grow below 5℃or above 40℃.The lethal temperature of conidial of S1,S3 and S4 strain was 54℃,10 min.and the lethal temperature of conidial of S2 was 52℃,10min. The mycelium could grow under the condition of pH 3 to 11.5,showing single peak curve, with the optimum pH range being between pH 4.5 to pH7.5.2.The pathogen could use many carbohydrates and nitrogen sources.For mycelial growth on solid media,the optimum carbon source was glucose,next being maltose and glycerol.Analysis of variance showed that there were significant difference(P＜0.05) between glucose and the others carbohydrates sources.The more suitable carbon sources for mycelial growth in liquid medium(mycelial dry weight)were soluble starch and glucose.Analysis of variance showed that There were very significant difference(P＜0.01) between soluble starch and the others carbohydrates sources.And for mycelial linear growth,the optimum nitrogen sources were peptone,next being NH4NO3 and NaNO3.The growth of T.roseum in liquid medium showed that peptone,as a sources of nitrogen,was optimum for mycelial growth.Analysis of variance showed that there were very significant difference(P＜0.01)between peptone and the others nitrogen sources.There were not different among the others nitrogen sources.3.The polyacrylamicide gel electrophoresis analysis of isozymes and soluble proteins of 6 isolates of T.roseum from different hosts were studied to compare their differences in isoenzyme zymogram and electrophoresis map.The results showed that there were clear differences in soluble protein electrophoresis map between different isolates in T.roseum, and that there were common two zymograms in 6 strains.It is suggested that electrophoresis technique was a useful tool in the classification of T.roseum could be used to classify T.roseum on both specific and infraspecific ranks.4.Pathogenicity of conidium of S1 strain had obviously strong than the others strain on condition of artificial inoculation in laboratory,reaching a extreme significant difference(P＜0.01)and pathogenicity of mycelial of S3 strain had obviously strong than the others strains on condition of artificial inoculation while there had no difference in the others strains.5.The inhibition activity of T.roseum had not been manifested in the dual-culture of itself and the tested pathogenic fungus,which indicated that the mycelial growth on solid media had no advantage than pathogenic fungus.However,the cultural filtrate of the T. roseum in the liquid culture showed powerful anti-fungal activity and broad inhibitory spectrum.The relative inhibitory effect on Sclerotinia sclerotiorum were 40.64%,58.98%, 100%When the cultural filtrate concentration were 6.25%,12.5%,25%respectively and were 25.00%,48.75%,100%when the disinfected cultural filtrate concentration were same.The relative inhibitory effect on Verticillium dahliae were 14.18%,53.15%,69.31% When the cultural filtrate concentration were 6.25%,12.5%,25%respectively and were 4.61%,27.80%,66.28%when the disinfected cultural filtrate concentration were same.It is tested that the inhibition activity of T.roseum mainly attributed to ferment substance. Therefore,T.roseum may be regarded as a very potential biocontrol agent. |
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