大白菜软腐病菌的运动状态与吸附的关系

THE SITUATION AND MOBILITY OF ERWINIA CAROTOVORA SUBSP. CAROTOVORA IN RELATION TO ITS ATTACHMENT

微分干涉显微镜观察表明,病菌(Erwinia carotovora subsp. carotovora Dye)在游离状态下的运动有直线运动、波浪运动和螺旋运动3种形式。菌悬液制备15分钟后,陆续出现病菌的纵向二联体,发生频率由最初占群体总量的0.02%增高到10%(10小时前后)和50～60%(24小时)。其间相继出现四联体、六联体及多至二十四联体。多联体运动的直线性增强,速度提高,多联体中每增加一个二联体,其运动速度就提高3～4倍。菌体运动与多联体形成的结果是使病菌在根表周围20微米内发生根向趋性运动,电镜扫描表明可由此导致在根表形成微菌落与细菌团。文章讨论了吸附前的病菌运动和多联体的形成对病菌在根际的富集作用、以及对吸附与侵染的动力学和生化学意义。

Observations under a differential interference microscope indicated that there were 3mobility forms of Erwinia carotovora subsp, carotovora, i. e. translational motion, swingingand tumbling. In 15 minutes after bacterial suspension preparation, longitudinally linkedbinary bacteria were found and increased gradually from 0.02% to 10% in 10h., and 50~60% in 24h. Following it, longitudinally linked poly-cell bacterial bodies were alsofound in forms of tetrad, hexad and up to twenty-four cell bodies. All of them were com-posed with the even number. The formation of poly-cell bodies increased bacterialmoving speed and translational motion. The result showed that adding a binary tothe poly-cell bodies would increase its moving speed for 3~4 times.Translational motion of bacteria and formation of poly-cell bodies would benefit tropismmovement of the pathogen toward root hair surfaces within a space of 20μm around them.By scanning with an electron microscope, this situation would also benefit the formationof bacterial micro-colony or mass on the root surface. The role of bacterial mobilityand poly-cell body formation in enrichment of pathogen around rhizosphere, the signifi-cance of those phenomena in dynamics and biochemistry of pathogen attachment and in-fection are also discussed.