箭舌豌豆根瘤中细菌衰老的研究

STUDY ON THE SENESCENCE OF BACTEROIDS IN VICIA SATIVA ROOT NODULES

箭舌豌豆根瘤中的细菌在开始衰老时,首先是细菌周膜增大,接着细胞壁变得不光滑,质膜附近出现大量含有纤维状物质的小泡。其中少数小泡体积特别大,几乎被纤维状物质充满,或将附近的细胞质连同其小泡一道卷入泡中,形成一个游离的细胞质小球。随着细菌进一步衰老,长度大大缩短,电子透明区显著减小,原生质结构消失并出现凝聚,形成一些电子密度很高的团絮状物质,而且在质膜附近还产生小的空泡。最后细菌完全解体,变成为一团泡状和膜状结构。

When Vicia sativa root nodule is senes-cing,their bacter-oidal ultrastructure appearsto have many changes.Firstly,the surfaces oftheir peribacteroid membranes obviously en-large,following,their cell walls become un-smooth and are often like wave-shaped andsawtooth-shaped.At the same time,a largeamount of small vesicles contained fibrillarmaterial locate near their plasma membranesbut the vesicles are very different in size andinclusions,some of them are specially large,some large vesicles contain abundant fibril-lar material,even are almost fulled by fibril-lar material,other large vesicles have a smallcytoplasmic ball which contain some smallvesicles with fibrillar material,the cytoplas-mic ball locates in the large vesicle centre.Companying the bacteroidal senescence,theirlength shortens,their width increases and thebacteroids tend to proximate round or oval.It is not only so but their electron-density isalso obvious decrease,their protoplasmic str-ucture has disappeared and forms some clu-stered electrondensity cotton fiber material,and there are some vesicles without fibrillarmaterial near their plasma membranes.Fina-lly,the senescent bacteroids completely disin-tegrate and become into some vesiclar-shapedand membrane-shaped structure.