培养条件对烟草赤星病菌产孢能力的影响

EFFECTS OF CULTURAL CONDITIONS ON SPORULATION OF TOBACCO BROWN SPOT PATHOGEN

用烟草赤星病菌13个菌株分别测定了3种基本条件对病菌产孢能力的影响。当病原真菌在8个温度梯度下生长时,产孢指数—温度曲线近S型,产孢的最低、最适、最高温度范围分别为12～16°、24～28°、32～36℃。当病菌在17个pH梯度下生长时,产孢指数—pH梯度曲线也近S型变化,最低、最适、最高pH范围一般分别为pH3.5～4.0、6.5～7.5、9.5～10.0。在三种光照条件下测定表明,暗处理可以明显增强病菌的产孢能力。另外,菌丝体损伤对产孢能力不发生明显影响。

Thirteen strains of Alternaria alternata, the pathogen of tobacco brown spot, were studied to testify their sporulating capability affected by temperature, pH condition and illumination. A Smodel curve of sporulation—temperature was established based on the sporulating indices of the pathogen strains cultured on PDA medium under 8 temperature gradients. The minimum, optimum and maximum temperatures for sporulation were 12～16, 24～28 and 32～36℃ crespectively. When the pathogen strains were grown under 17 pH gradients, their sporulating capability varied as pH varied, showing a S-model curve of sporulation—pH gradient, with mini., opti. and maxi. temps for sporulation of pH 3.5～4.0, 6.5～7.5 and 9.5～10.0 resp. The sporulating capability could be enhanced by darkness treatment, while injuring mycelia gave no effect.