温湿度及土壤类型对土壤中绿僵菌孢子萌发的影响

Influence of Temperature, Moisture, and Soil Type on Conidium Germination of Metarhizium pingshaense in Soil

平沙绿僵菌Metarhizium pingshaense是一种潜力巨大的生防真菌,绿僵菌能否在土壤环境下快速定殖是有效控制地下害虫的重要条件,而孢子萌发是定殖的第一步。本文研究了土壤温、湿度及竹林土、河滩土和农田土等3种土壤类型对绿僵菌孢子萌发的影响,并利用土壤平板法观察了孢子在土壤中的生活周期。结果表明,土壤温度和湿度对孢子萌发影响显著,土壤类型对孢子萌发影响较小。在供试3个土样中,在最适温、湿度条件下,孢子萌发率均可达到80.0%以上。土壤类型不同,适宜孢子萌发所需的温、湿度不同,竹林土最适温度为25℃,随湿度增加孢子萌发率增加,湿度24%时孢子萌发率最高为80.8%;农田土最适温度为25℃,随湿度增加孢子萌发率降低,湿度6%时孢子萌发率最高为86.5%;河滩土最适温度为30℃,随湿度增加孢子萌发率降低,湿度6%时孢子萌发率最高为80.0%。土壤类型与土壤温、湿度的互作对孢子萌发有显著影响,绿僵菌孢子在25℃、土壤湿度12%条件下,12 h开始萌发产生芽管,24~96 h为营养生长期,120~144 h为生殖生长期,之后开始产孢,168 h即可观察到链状分生孢子。

The conidia germination of Metarhizium pingshaense is an important factor to control soil pests. The effects of soil temperature, moisture and type on conidia germination and the life cycle of M. pingshaense in soil were investigated in this research. The results showed the main factors of conidia germination were soil temperature and moisture, followed by soil type. Under the most optimum temperature and humidity condition, the conidia germination ratios were more than 80.0% in bamboo forest soil, farm soil and riverside soil. The optimum temperature and moisture for conidia germination were different in different soil types. In bamboo forest soil, the conidia germination rate increased with soil humidity and reached 80.8%with moisture of 24%at the most optimum temperature of 25℃. In farm soil, the conidia germination rate was negative correlation with the moisture and reached 86.5%with moisture of 6%at the most optimum temperature of 25℃. The most optimum temperature for conidia germination was 30℃ in riverside soil. The conidia germination rate was negative correlation with the moisture and reached 80.0%when the moisture was 6%. The life cycle of M. pingshaense in soil was observed at 25℃and with moisture of 12%. The results showed that germ tubes was produced at 12 h, 24-96 h for the vegetative growth stage, 120-144 h for reproductive growth stage and then initiation of sporulation, catenulate conidia observed at 168 h.