The Preliminary Research On Effect And Mechanism Of Pleurotus Djamor Atagonizing Exserohilum Turcicum

In this experiment, the assay of antagonism(including confront culture test, enclosed chamber test and observation of the interaction between their hypha)between Pleurotus djamor and Exserohilum turcicum were carried out. The results indicated that Pleurotus djamor can efficiently inhibit the growth of mycelia of Exserohilum turcicum.The results of the optimal carbon source test, the optimal nitrogen source test and orthogonal test for Pleurotus djamor showed that the optimal carbon source was corn starch, the optimal nitrogen source was soybean powder, the optimal composition of the medium was corn starch 2%, soybean powder 1.5%, sucrose 3%, peptone 0.2% and primary pH5.5, and the effects of corn starch, sucrose, peptone, soybean powder and primary pH on the mycelial growth weakened gradually. Mycelial growth curve indicated the mycelial growth rate was the fastest, when Pleurotus djamor was incubated for 5-10 days. The culture of this phase is the best as inoculum in fermentation, and the mycelial yield of Pleurotus djamor was the highest after incubation for 15 days.The inhibiting effects of fermented culture broth of different treatment of orthogonal test against the mycelial growth of Exserohilum turcicum proved the fermented culture broth had the strongest antagonism against the mycelial growth of Exserohilum turcicum, when the medium ingredient was following: corn starch 2%, soybean powder l%,sucrose 1%, peptone 0.1% and primary pH5.5 ,and the inhibiting effects of corn starch, soybean powder, peptone, sucrose and primary pH against the mycelial growth of Exserohilum turcicum weakened gradually.There was a significant positive correlation between the mycelial biomass of Pleurotus djamor and the inhibiting rate of fermented culture broth against the mycelial growth of Exserohilum turcicum .and the regression equation was following: y=0.6345+34.011x,correlation coefficiency R~2=0.9998~*.The ontent of antagonism substances was the higuest after culture 17days.The crude protein in the fermented culture broth strongly inhibited the mycelial growth of Exserohilum turcicum but coarse polysaccharides can not. The fermented culture broth inhibited the conidial germination of Exserohilum turcicum, and approximated to the inhibiting effect of the dilution of 75% baijunqing powder or 50% duojunling powder. The fermented culture broth had quite strong thermal stability, and strongly inhibited the conidial infection to corn leaves in sand and pot experiments.