梨黑斑病病原菌生物学特性研究

Study on biological characteristics of Alternaria alternata caused occurrence of pear black spot

对梨黑斑病病原菌链格孢菌(Alternariaalternata)生物学特性的研究结果表明,不同菌株在PSA平板上培养,平均日生长速率、产孢量、菌落颜色以及菌落厚度有显著不同。病原菌生长适宜温度为20～30℃,最适温度为28℃,孢子萌发的最适温度为28℃;病原菌适宜生长相对湿度为50%～100%,最适生长相对湿度为98%～100%,孢子萌发必须具备相对湿度98%以上的高湿条件,在水滴中萌发率最高;病原菌菌丝适宜生长的pH值为4～12,最适生长pH值为7～8,孢子萌发最适pH值为7～8,病原菌培养一段时间后培养基的pH值会发生改变。该病原菌对多种单糖、双糖和多糖等碳源及有机氮、无机氮均可利用,最适碳源为蔗糖,最适氮源为蛋白胨,硫酸胺和氯化胺会抑制病原菌菌丝生长。

Biological characteristics of A Iternaria alternata, which causes the occurrence of pear black spot, were studied. The results indicated that there was significant difference in growth characteristics （including： growth rate, quality of spore, color of colony and thickness of colony） in PSA media. The suitable temperature for mycelia growth was 20-30℃, and the optimum was 28℃ ; the optimum temperature for spores germination was 28℃. The suitable relative humidity of mycelia growth was 50%-100%, and the optimum humidity was 98%-100%; only under high relative humidity condition, spores could germinate; especially in water drop, the germination rate of spores is high. The suitable pH value for mycelia growth was 4-12, and the optimum pH value was 7-8. The pH value of PSA could be changed by A. alternata after culturing. The optimum pH value for spores germination was 7-8. A. alternata could make use of many carbohydrates and nitrogen sources, the optimum carbon source was sucrose, and the optimum nitrogen source was peptone, while（NH4）2SO4 and NH4Cl would inhihit mycelia growth.