The Study On Effect Of Different Environmental Conditions On Beauveria Bassiana Strain SJ-05

The research determined the sporulation quantity, the growth rate and the germination rate of five Beauveria bassiana strains, which is isolated from Holcocerus. It determined the sporulation, the growth rate and the stability of artificial subculture on different medias of the superior strain. The results showed that, the strain SJ-05 was better than others. Based on the determination of indexes for strain SJ-05 on different medias, the most suitable medium of strain SJ-05 was PPDA medium.The regression equation of absorbance(x) and count(y) from hemocytometer counting was y=100.9589x+0.2838 (r2=0.9195).In measuring proceeding, the conidial suspension should be diluted by 1000 fold. The fitting equation of the strain SJ-05 under the thermal stress of 50℃was that Is= 1.0089/[1+exp(-3.6571+0.207812t)],and the median lethal time was 18.2min. It showed that the heat tolerant ability of strain SJ-05 is high.The research showed that: the effect of subculture on germination of the strain SJ-05 was to prolonged the time of germination. The optimum nutrient solution for the conidiophore germination of the strain SJ-05 was 1% chrysalis in capsules, the optimum temperature was from 25℃to 30℃. the optimum pH was from 6 to 8. In the research of the germinate on strain SJ-05 in low humidity, when RH was 72% the time of spores germinated completely is 3 times for which when RH was 100%. And when RH was 61%, the germination is 0. Within 10h under the UV burned, the protection of 0.10% Fluorescent brightener and 0.15% Vc were better than others. But more than 10 hours, the protection of 0.15% Vc is better than 0.10% Fluorescent brightener.