Abstract: Some oncogenic Agrobacterium strains have positive reaction of 3-ketola-ctate on DYL medium and good growth ability in YBS medium with sucrose as carbon source. Other oncogenic Agrobacterium strains have negatiye reac- tion of 3-ketolactate reaction and bad growth ability in YBS medium. Using this relation, an oncogenic Agrobacterium strain K-8 was isolated from fresh and young crown gall of peach tree with media DYL and YBS. Four oncoge- nic strains isolated from China had been determined. The strain S-1 and strain B-1 are strains of Agrobacterium tumefaciens Biotype I. The strain K-8 and strain 702 are strains of Agrobacterium tumefaciens Biotype II.

Key words: isolation, oncogenic, agrobacterium, preliminary

摘要： 利用3-酮基乳糖反应特性和对不同碳源培养基上生长能力的相关性，用DYL和YBS培养基从桃树新鲜幼嫩的冠瘿中分离到具致癌力的土壤杆菌K-8菌株．对四株国内分离的致癌菌株鉴定，确定菌株S－1、B－1为根癌土壤杆菌生物Ⅰ菌株，而K－8和702为根癌土壤杆菌生物Ⅱ型菌株．

关键词: 致癌, 土壤, 杆菌K-8菌株, 分离, 鉴定