大蒜紫斑病菌的分离及培养条件研究

Isolation of Alternaria porri(Elliott) Cif. and Study on Its Culture Conditions

从田间具有典型病斑的发病大蒜叶片上分离病菌并培养,形态和致病性鉴定结果表明,得到的病菌为大蒜紫斑病病菌,属葱链格孢（Alternaria porri（Elliott）Cif.）。培养条件研究表明,病菌在马铃薯葱汁琼胶培养基上生长速率最快,产孢量也最多;菌丝生长的适宜温度范围为22-30℃,低于18℃或者高于37℃均不适宜生长,菌丝培养的最适温度为26℃;病菌产孢的适宜温度范围为20-26℃,产孢培养的最适温度为22℃。菌丝在光暗交替条件下生长最快,在连续黑暗条件下产孢最多;在pH5-12范围内均能生长和产孢,以pH8产孢最多。

The pathogen was isolated from pathogenic and typical spots of garlic leaves in the field. The morphological and pathogenic identification of the pathogen showed that the pathogen is Alternaria porri （Elliott） Cif. The culture condition investigation showed the growth speed of the pathogen is the fastest on PSSA medium. The number of sporulation is also the largest on PSSA medium. The optimum temperature for mycelium growth is in the range of 22-30℃. It is not suitable for mycelium growth under 18℃or over 37℃. The optimum temperature for mycelium growth culture is 26℃. The optimum temperature for spore production is in the range of 20～26℃. The optimum temperature for spore production culture is 22℃. The mycelium growth speed is the fastest under the alternate condition of light and dark. But under the continual dark, the number of sporulation is the largest. The pathogen can grow and sporulate at the medium pH value between 5 and 12, but the number of sporulation is the largest at pH 8.