箭舌豌豆根瘤液泡中细菌周膜来源的研究

STUDY ON THE ORIGIN OF PERIBACTEROID MEMBRANE OF BACTEROIDS IN VACUOLES IN VICIA SATIVA ROOT NODULES

电镜观察结果表明,幼龄箭舌豌豆根瘤侵染细胞的细胞质较少,中央是一些体积较大的液泡。细胞质中侵入线经常可见,由侵入线释放出来的细菌均有细菌周膜。这些细菌只位于细胞质中,不出现在液泡里面。成熟根瘤中的侵染细胞与此不同,它们中有大量的成熟侵染细胞,细胞质丰富,里面充满大量细菌,中央常有一个大液泡。当中央液泡发育到一定程度时,位于其附近的细菌可通过液泡膜内吞、液泡膜与细菌周膜融合及液泡膜破裂3种途径进入液泡,后一种途径常伴有寄主细胞质。液泡中的细菌绝大部分裸露在外,只有个别细菌具有细菌周膜且多位于液泡膜的破损处附近,因此细菌周膜可能是原来就有的。

The infected cells in young Vicia sativa root nodules possess a small amount of cytoplasm, their central parts are some larger vacuoles. Infection threads in host cytoplasm are often observed, they usually contain some bacteria and conti-nuousely release them to host cytoplasm, but the bacteroids only are to appear in host cytoplasm, never in vacuoles and the bacteroids all possess peribacteroid membranes which come from their infection thread membranes. Mature root nodules do not differ from young root nodules, they contain a large quantity of mature infected cells which possess abundant cytoplasm and many bacteroids, larger vacuoles have disappeared, some smaller vacuoles have appeared. Companying the development of infected cells, smaller vaculoes start fusion each other, finally they become into some large central vacuoles. When the central vacuoles further develope to certain degree, sorne bacteroids in host cytoplasm enter to central vacuoles by three formations, namely tonoplast endocytosis, fusion of tonoplast with peribacteroid membrane and tonoplast break, last one often companies with some host cytoplasm. Absorbute majority of bacteroids in central vacuoles do not possess peribacteroid membranes, only individual bacteroids have the structure and the better the peribacceroid membrane is the clearer the structure of the bacteroid is. The bacteroids with peribacteroid membrane often locate near the break places of tonoplast, they usually not in the central parts of the central vacuoles. Therefore, peribacteroid membrane may be originally possessive but not formed in vacuole.