绿僵菌在3种不同培养基上培养时产孢量的影响因素

分析了绿僵菌菌株在3种不同培养基上培养时其产孢量的2个影响因素(初始接种浓度和相对湿度),得出菌株在3种不同培养基上培养时须分别配以适宜的接种浓度和相对湿度,以获取最大产孢量(燕麦培养基:1×107cfu/mL,65%;PPDA培养基:1×106cfu/mL,85%;玉米粉酵母浸膏培养基:1×108cfu/mL,75%)。另外,随继代培养代数增加,菌株在这3种培养基上前五代的产孢量比较稳定,第七代及之后的产孢量明显下降。根据3种培养基不同的功能,在PPDA培养基上培养菌株时要着重注意不同继代培养代数对产孢量的影响,其它2种培养基培养菌株一般不超过五代,产孢量比较稳定。

The Factors Affecting the Sporification of Metarhiziums spp. Strains Cultured in Three Different Mediums

Metarhiziums spp. is a broad spectrum entomopathogenic fungus, and it is thus of great significance to increase sporification of this fungus. Two factorsinoculation concentrations and relative humidity (RH)]affecting the sporification of Metarhiziums spp. strains grown in 3 different mediums were determined. The results showed that these two factors were very important for maximum sporification of this fungus on these three mediums. Maximum sporification occurred when the fungus were cultured on the oats medium at the inoculation concentration of 1×107 cfu/ml and RH 65%; on PPDA medium at the inoculation concentration of 1×106 cfu/ml and RH 85%; or on the corn powder and yeast soaking flour medium at the 1×108 cfu/ml and RH 75%. Moreover, this fungus when subcultured under these mediums and conditions had higher and stable volume of spores in the first 5 generations of the subculture but produced less spores in and after the 7th generation of subculture. According to the different functions of the 3 mediums, the subculture generation greatly affected the sporification in the PPDA medium, and lightly affected other two mediums unless the subculture overtakes the fifth generation.