烟草白绢病菌生物学特性的研究

经研究观察烟草白绢病菌(Sclerotium rolfsii Sace)菌丝生长温度范围为10-40℃,适宜温度30-33℃。菌核萌发温度13-40℃,适宜温度25-35℃。病菌生长相对温度范围为62.5-100%,适宜温度93-98%。菌丝的致死温度为48℃ 10分钟,菌核为50℃ 10分钟。病菌生长pH值范围2-9,适宜pH值3-7,最适为pH5。菌丝在黑暗条件下生长较快,光照对菌核的形成有利。病菌对紫外线菌丝比菌核敏感。病菌生长适宜的培养基为PDA和PSA,最需要的矿物质元素是碳,其次是氮、磷、钾和铁;对镁不需要,最好的碳源是蔗糖、淀粉和葡萄糖;最好的氮源是酵母膏,蛋白胨次之,有机氮明显好于无机氮,对硝态氮利用好于氨态氮。 

Study on the Biological Characteristics of Tobacco Southern Stem Rot Pathogen

The pathogen of tobacco southern stem rot caused by Sclerotium rolfsii Sace has been studied. The growth temperature for hyphae is 10-40℃, the optimum temperature is 25-35℃. The growth humidity for pathogen is 62.5-100% and optimum humidity is 93-98%. The fatal temperature of hyphae is 48℃ (within 10 minutes), and the fatal temperature of sclerotia is 50℃ (within 10 minutes). The growth pH value for the pathogen is 2-9. The pretkrence pH value is 3-7, and optimum pH value is 5. The hyphae grow is faster in darkness, but light is good for sclerotia formation. The pathogen is aerobiotic. The hyphae are more sensitive to ultraviolet light injury than sclerotia. Optimum medium for pathogen growth are PDA and PSA. The importance of the mineral nutritions for pathogen growth was shown in the order of C, N, P, K and Fe. Mg is useless for the pathogen. Among 5 carbon source, sucrose, starch and glucose are better than others. Among 5 nitrogen source, yeast extract and peptone are better than others. Organic nitrogen sources are better than inorganic nitrogen sources. NO₃-N is better than NH₄-N.