【摘要】 【目的】弄清冰核活性细菌(INA细菌)在杏树上分布种类及分布与年消长动态规律,对于通过防治INA细菌防御杏树晚霜冻害具有重要的意义。【方法】对北京杏主产区27个杏栽培品种及山杏进行调查,采用形态及生理生化方法进行种类鉴定,采用小液滴冻结法测定冰核活性。【结果】共分离到22株-5℃有活性INA细菌菌株,被确定为2个属中的3个种:假单胞菌丁香致病变种(Pseudomonas syringae pv.syringae)10株,占45.5%;成团泛生菌(Pantoea agglomerans)9株,占40.9%;凤梨泛生菌噬夏孢子致病变种(Pantoea ananas pv.uredovora)3株,占13.6%。成团泛生菌为杏树上首次发现的INA细菌,‘玉巴达’杏树上的INA细菌(P.agglomerans)数量分布存在3个高峰期:花期(3月末至4月初)、果实发育期(5至6月初)、越冬初期(12月),夏秋季及寒冬难以分离到INA细菌。【结论】INA细菌分布数量与杏树所处地理位置及生态条件有关,杏不同器官上分离到的INA细菌的频率也存在差异。更多还原

【Abstract】 【Objective】 For prevention of frost damage to apricot trees, it is important to investigate the species of ice nucleation active bacteria (INA bacteria) and their distribution and dynamics throughout the whole year. Method】The species of INA bacteria and their distribution were studied on 27 apricot cultivars of Prunus armeniaca and on P. ansu. Dynamics throughout the whole year were investigated on ‘Yubada’ in an orchard in Haidian District. The species of INA bacteria were identified based on their morphological, physiological and biochemical characteristics. Ice nucleation activity was determined by a droplet freezing assay. Suspensions of 48 h cultures were made with ice nucleus-free sterile distilled water and adjusted spectrophotometrically to about 108 cfu/ml. Thirty 10 μl drops of each suspension were placed on wax-coated aluminum foil boats. They were brought to -5℃ by floating the boats for 3 min on a alcohol solution maintained at (-5±0.05)℃ in a thermostatically controlled bath. Isolates were identified as INA bacteria if 30% of its’ droplets frozen at -5℃.【Result】Twenty-two strains of INA bacteria, isolated from apricot trees in Beijing, were identified as three species belonging to two genera: 10 strains of Pseudomonas syringae pv.syringae, 9 strains of Pantoea agglomerans, 3 strains of Pantoea ananas pv.uredovora, accounting for 45.5%, 40.9%, 13.6% of total amount, respectively. P. agglomerans was first discovered as an INA bacteria on apricot trees. There were three peaks of INA bacteria population throughout the year during flowering (end of March to beginning of April), rapid fruit growth (May to beginning of June) and early stage of overwintering in December. 【Conclusion】The distribution and frequency of INA bacteria varied with geographic position, ecological conditions, and organs of apricots.更多还原