蝉蜕诱导对球孢白僵菌生物学特性及其毒力影响的研究

利用改良蝉蜕诱导培养基对球孢白僵菌进行诱导，以无蝉蜕PDA培养基作为对照，目的是比较蝉蜕诱导后球孢白僵菌菌株的生长速率、产孢量、孢子萌发率等多个生物学指标，及二者对3龄亚洲玉米螟幼虫的毒力。经蝉蜕诱导的球孢白僵菌菌株的产孢量、孢子萌发率以及对玉米螟幼虫毒力都高于对照组，且差异显著，对玉米螟幼虫毒力处理组LT₅₀为4.73天，对照组需要6.97天。同时经蝉蜕诱导过的菌株开始产孢时间和胞外蛋白酶活性都优于对照组，胞外蛋白酶活性的变化范围是1.497×10^-2~3.538×10^-2 IU/mL，但经诱导菌株的生长速率低于处理组。鉴于球孢白僵菌菌株经蝉蜕诱导后，其产孢量和孢子萌发率增加，并且能够增强对玉米螟幼虫毒力，可利用其进行球孢白僵菌菌种保存和改良。

Research on Effect on Biological Characteristics and Virulence of Beauveria bassianaInduced by Periostracum Cicadae

Improved medium contained Periostracum Cicadae was used to induce the entomogenous fungus Beauveria bassiana, with the PDA medium as control. The growth rate, sporlation, spores germination and virulence against the third?instar?larva of Ostrinia nubilalis of the fungus were compared on both medium. The results indicated that sporlation, spores germination and bioactivity against pests induced by P. Cicadae were higher than that of the control, respectively, and showed significant difference. LT₅₀ of fungus induced by P. Cicadae against the pests was 4.73 days, and that of the control was 6.97 days. In addition, the sporulation time of the fungus induced and extracellular protease activity by improved medium was better than those of control group, The variation range of extracellular protease activity by improved medium was 1.497×10^-2-3.538× 10^-2 IU/mL, but trowth rate of the former was lower than that of the later. In conclusion, the sporlation, spores germination, and virulence against pests were enhanced by P. Cicadae induction, it was potential for storage and improvement of B. bassiana strain.