三七根腐病复合侵染中病原细菌的研究

 报道三七根腐病复合侵染中病原细菌的研究结果。病菌从根部侵入,引起根腐,叶片褪绿变黄或青枯,病菌随病残体、土壤和种苗传播。病菌在金氏B培养基上菌落圆形,灰白色,略凸起,边缘整齐,半透明,湿润光滑,不产生荧光色素,菌体杆状,直或稍弯,革兰氏染色阴性,具1～6根极生鞭毛。积聚β羟基丁酸盐颗粒,氧化酶、精氨酸双水解酶呈阳性,烟草过敏反应,马铃薯软腐阴性,人工接种发病症状与田间症状相似,发病率达90%以上。经鉴定,该菌为假单孢杆菌(Pseudomonas sp.)。

Studies on Pathogenic Bacteria in ComplexInfection of Panax notoginseng Root Rot

This paper is the results of studies on pathogenic bacteria in complex infection of Panax notoginseng root rot.Bacterial invasion occurs at the roots,and the stem end of the tuberous root.Root rot may be accompanied by leaf chlorosis or a green wilt.The bacterium can be spread by plant debris,infected soil,or infected seedling.Smooth,butyrous,palecolored colonies were consistently isolated from disease tissue on Kings medium B.Bacteria were straight or curved.Gram negative rods with 16 polar flagella.No fluorescence pigment was observed.Fifteen representative isolates were positive for polyhydroxybutyrate granules,oxidase,arginine,dihydrolase,catalase,and nitrate reduction.They were negative for levan.Tween 80 hydrolysis,lecithin are production,and gelatin hydrolysis.The isolates induced a hypersensitive reaction in tobacco,and did not rot potato slices.Oneyearold plants were inoculated by immersing rinsed roots in bacterial suspensions containing 108 CFU/mL.Inoculated plants were then transplanted i n 10 cm125 cm paper bags and grown at 2227Test plants were covered with polyethylene film for 48 h.Symptoms observed 9 days after inoculation included green wilting,yollow leaves,root rot,and plant death,as the symptoms in fields.Mortality of inoculated plants ranged from 900%