白菜黑斑病菌（Alternaria brassicae）菌丝生长和毒素产生条件的研究

对白菜黑斑病菌（Ａｌｔｅｒｎａｒｉａｂｒａｓｓｉｃａｅ）不同菌株的营养生长和产毒条件的研究结果表明，白帮菌系（ＡＢＷ）与青帮菌系（ＡＢＧ）的生物学特性有一定的差异，同一菌系菌株间差异不显著，其中ＡＢＷ菌丝生长的最佳条件是２０～２２℃、ｐＨ４、光照１２ｈ／ｄ、间歇振荡和以蔗糖（浓度为３％）为Ｃ源；而毒素产生的最佳条件是１３～１５℃、ｐＨ６、黑暗、静止和以葡萄糖（浓度为１０％）为Ｃ源。ＡＢＧ菌丝生长的最佳条件是１３～１５℃、ｐＨ４、光照１２ｈ／ｄ、全天振荡和以蔗糖（浓度为３％）为Ｃ源；而毒素产生的最佳条件是１３～１５℃、ｐＨ４、黑暗、静止和以葡萄糖（浓度为５％）为Ｃ源。研究还发现，相同条件下ＡＢＧ的菌丝生长速度均大于ＡＢＷ，而产毒量却较为复杂。青帮品种比白帮品种白菜更易感染白菜黑斑病菌。此外，白菜黑斑病菌生长后的改良Ｆｒｉｅｓ培养基ｐＨ值均有变小的趋势，而且随着菌丝生长量的增加变化幅度逐渐增大。

Factors Affecting Hyphae Growth and Toxin Production of Alternaria brassicae

The factors affecting hyphae growth and toxin production of two strains of Alternaria brassicae have been researched in this paper. The experimental results showed that the biological characteristics were different between white cabbage strain (ABW) and green cabbage strain (ABG)of A. brassicae but there was little difference among different isolates within the same strain. The fittest conditions of ABW hyphae growth and toxin production were 20～22℃, pH4, light 12 hours one day, interval shaking culture, 3% sucrose as C resource and 13～15℃, pH6, dark, stilling culture, 10 % glucose as C resource respectively.The fittest conditions of ABG hyphae growth and toxin production were 13～15℃,pH4、light 12 hours one day. shaking all the day, 3% sucrose as C resource respectivelly. The results suggested the rate of ABG hyphae growth was quicker than that ofand 13-15℃,pH4, stilling culture, 5% glucose as Cresourece, ABW at the same conditions, but the toxin production was complex, and green cabbage was more susceptible to A. brassicae than white cabbage. Further more, the pH value of the modified Fries medium after inoculating A. brassicae was turned smaller,and the more hyphae growing,the bigger the alteration was.