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将大白菜种子置于培养皿内的滤纸上发芽。滤纸用不同浓度的洗涤与不洗涤的软腐欧氏杆菌(Erwinia carotovora pv.carotovoar Dye)悬浮液,离心上清液,培养基浸出液和灭菌生理盐水浸润。在25℃下培养26小时后,用细菌悬浮液处理的幼芽发病率为8—95%不等。病苗生长量为对照(用生理盐水处理)的17—80%。扫描电镜观察的结果指出,接种后病原细菌首先在根毛区发现,以后才在伸长区和成熟区发现大量病菌。成熟区表皮细胞与细胞交界处的细胞壁有被分解的迹象。在幼苗的导管及其附近的薄壁细胞内均发现了病原细菌,检出率分别为16%和3%。在病苗组织内和幼根表面的病菌可产生微纤丝。病苗幼茎经压气处理24小时后,对其断面进行扫描电镜观察,结果表明,病菌可将导管的外壁与纹孔膜分解而使导管解体仅剩螺蚊加厚部分或呈网孔状。
Germinating cabbage seeds on filter paper in a Petri dish. The filter paper was infiltrated with various concentrations of Erwinia carotovora pv. Carotovoar Dye washed and non-washed, centrifuged supernatant, medium leachate and sterile saline. After 26 hours of incubation at 25 ° C, the incidence of young shoots treated with the bacterial suspension ranged from 8-95%. Saplings grew 17-80% of the control (treated with saline). The results of scanning electron microscopy showed that after inoculation, the pathogenic bacteria were firstly found in the root hair area, but later a large number of pathogens were found in the elongation and mature areas. Mature zone of epidermal cells and cell junction cell wall has been decomposed signs. Pathogenic bacteria were found in the duct of the seedlings and in the nearby parenchyma cells, with detection rates of 16% and 3%, respectively. Pathogens in the tissue of seedlings and on the surface of young roots produce microfibrils. The young shoots of the vaccine seedlings were treated with compressed air for 24 hours. The sections were observed by scanning electron microscopy. The results showed that the bacteria could decompose the outer wall of the catheter and the pellucid membrane, leaving only the thickened part of the catheter or mesh-like shape.