Abstract: The electron-microscopic observation indicated that the uninfected cell of supernodulating soybean had an obviously enlarged nucleus. The younger bacteroid was elliptic and had a similar nucleus region in cell. The normal bacteroid had an intact membrane envelope and PHB granules. There appeared similar abnormal phenomena of ineffective nodule in infected host cell. which few bacteroids degenerated and were lytic, and there were empty membrane envelopes and bare bacteroids. The decrease of nitrogenase activity in supernodulating soybean might result from above-mentioned abnormal phenomena.

Key words: Supernodulating soybean, Nodule, Ultrastructure

摘要： 电镜观察表明,超结瘤大豆未受侵染的宿主细胞中有一明显增大的细胞核。幼年美菌体为椭圆形,里面有个拟核区,正常类菌体有完整的周膜和PHB颗粒。受侵染的寄主细胞中出现类似无效根瘤的异常现象:少数类菌体退化或溶解,还有空周膜及裸露的类菌体,这可能是超结瘤大豆固氮活性较低的原因。

关键词: 超结瘤大豆, 根瘤, 亚显微结构