为明确温度对绿僵菌LA菌株生物学特性和毒力的影响,采用微室萌发、酶标仪测定A值以及体外涂抹法,对不同温度下LA菌株孢子萌发率、胞外蛋白酶、几丁质酶活力以及对东亚飞蝗的毒力进行了测定,结果表明:LA菌株在30℃下孢子萌发速率最快,对东亚飞蝗的致死速率也最快;38℃下培养,孢子萌发率开始受到限制,40℃下培养孢子的萌发率接近于0;高温处理转至适温培养,对孢子萌发速率产生一定影响,48℃下处理不同时间,孢子萌发速率、萌发率均显著降低,转至30℃下培养24h仅有10.6%~20.9%的孢子可萌发;LA胞外蛋白酶活力培养至第6天达到最高,为31.37U/mL,不同温度下活力测定表明37℃下胞外蛋白酶活力最高,几丁质酶在培养至第5天酶活力达到最高,为34.62U/mL,最高酶活温度为50℃。
To clarify the influence of temperature on biological character and virulence of Metarhizium anisopliae LA isolate, we adopted the methods of mini-cell germination, A value measurement with enzyme mark instrument and in vitro smear to study conidial germination rate, extracellular protease activity and chitinase activity, virulence to Locusta migratoria manilensis at different temperatures. The results showed that the germination velocity of LA isolate and lethal velocity to L. migratoria rnanilensis were fastest at 30 ℃. Cultivated at 38 ℃, the conidial germination rate began to be restricted. At 40 ℃, the conidial germination rate was closed to zero. High temperature had some influences on conidial germination. Treating LA conidia at 48 ℃ with different periods of time, the germination velocity and rate were both reduced. Transferred to 30 ℃ and cultivated 24 h, there were only 10.6%-20.9% conidia which could germinate. Protease activities reached to the highest after being cultivated 6 days at 37 ℃. Chitinase activities reached to the highest after 5 days at 50 ℃.