环境因素对香蕉叶斑病菌喙突脐蠕孢生长和产孢的影响

Effects of environmental factors on growth and sporulation of Exserohilum rostratum causing banana leaf spot disease

为进一步明确香蕉叶斑病菌喙突脐蠕孢的生物学特性,调查了部分环境因素(碳氮源、植物成分培养基)对供试菌株(CLER09、D087和JL05)的营养生长和产孢的影响。结果显示,分生孢子主要先从基部萌芽,在28℃下约培养10h后出现两端萌芽;供试菌株对测试的20种碳源及26种氮源显示相似的生长反应,均可利用除菊糖外的测试碳源及氮源进行营养生长和产孢;测试的6种植物成分培养基对供试菌株的营养生长效果皆优于PDA培养基;除燕麦培养基外,其余5种培养基对菌株CLER09和D087的产孢作用均优于PDA培养基;测试的6种培养基对菌株JL05的产孢作用均优于PDA培养基。不同植物成分培养基对该菌分生孢子形态影响较大,以米糠、象草培养基对菌株D087和JL05的分生孢子长度和玉米粉培养基对菌株CLER09的分生孢子宽度的增长效果最为明显。

For the purposes of further indepth understanding of the biological characters of Exserohilum rostratum causing banana leaf spots, the influence of partial environmental factors （carbon sources, nitrogen sources and plant extracts） on growth and sporulation of 3 tested isolates （CLER09, D08 and JL05） were investigated. The results indicated that most of the conidia first germinated from the base, and bipolar germinations occurred after 10h of incubation at 28℃. All of the tested isolates showed similar growth reactions on utilizing 20 carbon sources and 26 nitrogen sources. They could utilize all of the tested carbon sources except inulin, and all of the tested nitrogen sources for their vegetative growth and sporulation. The vegetative growth of the isolates were better on 6 tested plant extract media as compared with potato dextrose agar （PDA） medium. All of the tested plant extract media were more suitable for sporulation of isolates CLER09 and JL05 as compared with PDA medium. Except oatmeal agar medium, the other 5 media were more suitable for sporulation of isolate D087 as compared with PDA medium. Conidial morphology was found to be significantly influenced by plant extract media. The conidial lengths of isolates D087 and JL05 markedly extended on rice bran agar and elephant grass agar, while the conidial widths of isolate CLER09 markedly broadened on cornmeal agar medium.