甘蓝种传尖孢镰刀菌粗毒素的研究

Effect of the crude toxin from seedborne Fusarium oxysporum on seed germination and seedlings of cabbage

为研究甘蓝感病（北农早生）和抗病（珍奇）品种种传尖孢镰刀菌Fusarium-CG和Fusarium-HM的培养滤液和粗毒素对种子发芽的影响,采用乙酸乙酯和乙醚萃取法提取粗毒素中的镰刀菌酸并利用HPLC法进行定量分析,利用粗毒素浸渍甘蓝幼苗根部测定其对幼苗的致枯萎作用。结果表明：Fusarium-CG和Fusarium-HM的培养滤液和粗毒素对种子的发芽具有明显的抑制作用;粗毒素浸渍甘蓝幼苗根部能够引起幼苗枯萎;其粗毒素中镰刀菌酸质量浓度分别为552和105μg/mL,并且粗毒素对甘蓝的致害作用随着镰刀菌酸含量的升高和处理时间的延长而加重,当用镰刀菌酸质量浓度为25μg/mL的粗毒素处理甘蓝幼苗24 h后,幼苗病情指数在2.6~15.9之间,而用镰刀菌酸质量浓度为100μg/mL的粗毒素处理甘蓝幼苗96 h后,幼苗病情指数在78.0~97.8之间。浸渍24 h时粗毒素对感病品种的致萎作用强于抗病品种,当用镰刀菌酸质量浓度为25μg/mL的Fusarium-CG和Fusarium-HM的粗毒素处理甘蓝幼苗24h后,抗病（珍奇）品种的病情指数分别为2.6和4.2,而感病（北农早生）品种的病情指数分别为15.2和15.9。

This paper is concerned on the effect of culture filtrate and crude toxin of cabbage seedborne Fusarium oxysporum（Fusarium-CG and Fusarium-HM） on the seed germination of cabbage.The used two cultivars were susceptible Beinongzaosheng and resistant Zhenqi.Fusaric acid in the crude toxin was extracted with ethyl acetate and diethyl ether,and was analyzed by HPLC.The toxic effect was tested through immerging the root of cabbage seedlings into the crude toxin.The results showed that either the culture filtrate or crude toxin of Fusarium-CG and Fusarium-HM significantly inhibited the seed germination of cabbage.The cabbage seedlings wilted after treated by the crude toxin,whose concentrations of fusaric acid for the two isolates were 552 and 105 μg/mL respectively.The toxic effect of the crude toxin on cabbage seedlings aggravated with increasing fusaric acid concentration and exposed duration.The disease index of cabbage seedlings was 2.6-15.9 when treated with crude toxin at a concentration of fusaric acid of 25 μg/mL for 24 h,but ranging from 78.0 to 97.8 when treated with a concentration of 100 μg/mL for 96 h.The wilting effect was more pronounced in the susceptible Beinongzaosheng than the resistant Zhenqi.The seedlings disease index were 2.6-4.2 and 15.2-15.9 for Zhenqi and Beinongzaosheng,respectively when treated with 25 μg/mL crude solution for 24 h.