大白菜软腐细菌潜伏侵染的研究

 大白菜贮藏期软腐(Erwinia carotovora pv.carotovora Dyc)是城市冷库贮藏中严重的病害问题。据在南京市蔬菜公司冷库调查,常年因软腐病引起的损失达总入库量的40%。三年来,对不同来源和品种的外表完全健康的大白菜进行厌气诱发检测,结果在近500株被测的大白菜植株中,潜伏带菌率达99.6%。对10株大白菜的所有叶片逐张进行检查的结果表明,内、外叶片都有潜伏侵染的细菌存在。叶平均带菌率为47.7%,最高为82.8%,最低为4.5%。将叶片用75%的酒精表面消毒1~3分钟,通常并不明显减轻叶片的腐烂。自然潜伏带菌的叶片,诱发发病后病斑多与叶脉作平行分布。对生长在两个试验区的共17个品种的大白菜分别进行潜伏带菌程度的比较,不同品种的大白菜在两块田中的潜伏带菌趋势基本上是一致的。对17个品种大白菜的发病情况,可将其分为较抗、中感和高感3个类型。

STUDY ON LATENT INFECTION OF CHINESE CABBAGE(BRASSICA PEKINESIS PUPR.) BY ERWINIA CAROTOVORA PV.CAROTOVORA DYE

Soft rot of Chinese cabbage was considerably severe in cold storage in Nanjing and caused loss to 40% as the total weight of the plants frenqently.Since 1982,500 mature plants without any visible symptom from fields,market and cold storage were examined with anaerobic technique and 99.6% of plants were found to be infected by soft rot bacteria.The examination of all detached leaves of 10 plants showed that the pathogenic bacteria were present in most of both outer and inner leaves of all the plants tested and the ratio of diseased plants was from 4.5% to 82.8% with a average value of 47.7%.The decay of the surface-steri-lized leaves due to the latent bacteria by the anaerobic technique was almost as severe as the decay of the non-sterilized leaves.The macerated lesions appeared in the petiole tissues in line parallel to the vascular bundles.17 cultivars of Chinese cabbage planted in two plots in Nanjing were investigated to compare the resistance to the latent bacteria.Latent infection of different cultivars from the two plots had a identical tendency basically and three groups in resistance could be divided based on severity of the soft rot.