苹果锈果病的病原

THE PATHOGEN OF APPLE SCAR PEEL DISEASE

从苹果锈果病枝条减压抽取出输导组织液,在其离心沉淀物的超薄切片中,电镜检查到形态类似立克次体的难养细菌(fastidious bacteria)。病株花柄和幼嫩果柄的超薄切片中也观察到这种细菌。健树制备的对照样品中没有。从锈果病带病者——梨树中也发现有这种菌。用难养菌液接种,苗木叶片表现典型的弯叶症状。青霉素处理有减轻病情的疗效。可以认为这种难养菌是引起苹果锈果病的病原物。

The fastidious bacteria were observed in thin sections of centrifugaters of vascular sap extracted from twigs of apple infected with apple scar peel disease (ASPD). They were also observed in thin sections of pedicels and tender fruit stalks of diseased apples. The bacteria were found within pears, the carriers of ASPD, as well. However, they have never been found in samples made from healthy apples. After inocu lation with the bacteria extracted from diseased apples, the apple saplings showed the downturn of leaves, a typical symptom of ASPD at the seedling stage. The symptoms of leaf downward curl and scar skin could be depressed considerably by treatment with penicillin.It is therefore considered that the fastidious bacteria observed seem to be the pathogen of ASPD.