【摘要】 采用浸胚根法和浸根法对京欣一号西瓜种壳分离得到的尖孢镰刀菌(Fusarium oxysporum)进行致病性试验。结果表明:从接种后发病幼苗上分离得到的分离物与最初接种所用的镰刀菌菌落形态和生长速率等性状基本相同,采用相同的引物对rDNA进行PCR扩增获得的核苷酸序列完全相同,说明这二者为同一种菌,从而证明西瓜种子上所携带的尖孢镰刀菌具有致病性,在国内首次报道了西瓜种传尖孢镰刀菌具有致病性。西瓜种传尖孢镰刀菌培养滤液和粗毒素提取物处理西瓜种子后,种子的发芽势、发芽率和发芽指数均显著降低,其中发芽势下降了16.7%~29.0%,发芽率下降了14.4%~22.3%,发芽指数下降了19.1%~37.1%,说明培养滤液和粗毒素提取物可影响西瓜种子发芽。更多还原

【Abstract】 The pathogenicity of Fusarium oxysporum isolated from the seed coat of watermelon seeds(cv.Jingxin No.1) was studied using radicle-dipping and root-dipping inoculation method.Morphological observation and molecular detection of isolates from diseased watermelon seedlings and the corresponding Fusarium used for inoculatation were carried out.The results showed that morphological characters including colony morphology and growth rate between the isolates and the corresponding Fusarium were approximately identical.Nucleotide sequences of PCR products of rDNA of the isolates and the corresponding Fusarium amplified by the same primers were exactly same.This showed that the isolates from diseased seedlings and the Fusarium used for inoculatation were the same.Thus,the Fusarium oxysporum isolated from the seed coat of watermelon seeds(cv.Jingxin No.1) is pathogenic.This is the first report that the seedborne Fusarium oxysporum can be pathogenic to watermelon.The effects of culture filtrate and crude toxin of this fungus on watermelon seed germination were also conducted.The germination energy,percentage germination and germination index of watermelon seeds decreased significantly after treatment with culture filtrate and crude toxin of the seedborne Fusarium oxysporum.The germination energy,percentage germination and germination index reduced by 16.7%-29.0%,14.4%-22.3%,19.1%-37.1%,respectively.The results indicated that culture filtrate and crude toxin of this fungus could affect the seed germination.更多还原