棉花黄萎病菌致病力变异生理机制的初步研究

The Preliminary Study of Variation Mechanism of Pathogenic Type of Verticillium dahliae Kleb.

在4种不同的温度下对31个致病力不同的菌株及落叶型菌株V991进行PDA平面培养,81.3%的强致病力类型菌株表现为菌丝型,落叶型菌株均为菌丝型,80.00%的中等致病力类型的菌株为中间型,弱致病力类型菌株均为菌核型。20～25℃有利于病原菌产生菌核,30℃的较高温度明显抑制菌核的形成。各菌株在25℃条件下菌落生长最快,分生孢子产量和毒素产量最高;30℃的较高温度下,强致病力类型菌株的菌落直径、分生孢子产量和毒素产量均显著大于中等致病力和弱致病力类型,且落叶型菌株高于非落叶型菌株。

31 strains of different aggressiveness and V991(a highly aggressive,defoliating strain)are cultured on PDA flat under four different temperature(15℃?20℃?25℃?30℃).The result indicated that 31 strains showed different characteristics on PDA flat, 81.25% strains of high aggressiveness are filament type (which produce much filament and a few nuclei),all of the defoliating strains are filament type, 80.0% strains of medium aggressiveness are medium type (which produce some nuclei)and all of strain of weak aggressiveness are nuclei type(which produce quite a few nuclei). Strains produce more nuclei under 20～25℃ than 30℃. Under four different temperatures strains produce fewer and fewer nuclei along with the generation going ahead, especially under 30℃.The speed of filament grow is more rapid, the sporulation production and toxin production are higher under 25℃ than 15℃ and 30℃. Under 30℃, the growth speed of filament of highly aggressive strains is more rapid, and the sporulation production and toxin production are higher than medium and weak aggressive strains.Under 25℃, toxin production of defoliating strains is obviously higher than nondefoliating strains. Under 30℃, the growth speed of filament of defoliating strains is more rapid, sporulation production and toxin production are obviously higher than nondefoliating strains. Defoliating strains can stand higher temperature(30℃).