北方杨树上冰核活性细菌的研究
A Study on Ice Nucleation Active Bacteria in Northern Poplars
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摘要: 从辽宁省、黑龙江省及北京市的杨树不同部位及干部溃疡类病害的病斑上分离到大量细菌.约有60%左右的菌株在-3.5~6℃具有冰核活性.其中,从树干冻伤部位分离的细菌数量最多,冰核活性细菌的比例也最高;由Dotheorella gregaria Sacc.引起的大型溃疡病病斑上也分离到较多的冰核活性细菌.用干部大型溃疡斑上分离到的1个冰核活性较强菌株Erwinia herbicola (Lohnis)Dye和叶部分离1个冰核活性强的菌株(Pseudomonas syringae VanHall),在人工霜箱中测定,可使杨树干条的结冰温度从-4.6℃分别提高到-2.2℃和-1.7℃.初步调查研究的结果表明,北方杨树上普遍存在着冰核活性细菌,它们在引起杨树冻伤过程中起重要作用;在诱发某些干部溃疡病过程中也可能有重要影响.Abstract: A number of bacteria had been isolated from different parts of poplar in Liaoning,Heilongjiang Province and Beijing City. About 60% of the bacteria strains showed ice nucleaticn activity under.5~6℃.Among them,the majority of the bacteria were isolated from the frozen bark of the poplars and most of them were INA bacteria,which could also be isolated from large canker lesions caused by Dotheorella gregaria Sacc.The overwintered one-year-old poplars were inoculated separately by Pseudomonas syringae isolated from the leaf or Erwinia herbicola isolated from large canker lesion. The freezing temperature of stems was tested under laboratorial simulation conditions. The stems inoculated by both of the INA bacteria suffered frost injury at -1.7℃ and -2.2℃ respectively,whereas the frozen state of the checks appeared at -4.6℃.The results showed that, INA bacteria were distributed widely in nprthern poplars. In the courses of frost injury,those INA bacteria exerted important effect on the formation of frozen barks.Probably they also have some influrences in the formation of large canker leslons.