大豆根瘤的扫描电镜观察

大豆与大豆根瘤处于一个共生的体系,大豆为大豆根瘤的生长提供适宜的微观环境,而大豆根瘤则为大豆植株的发育提供必要的养分.豆科植物的生物固氮能力是通过根瘤菌的侵染完成的.大豆根被根瘤菌侵染后,形成共生体根瘤,根瘤菌通过生物固氮作用将空气中的氮转化为氨供给大豆利用.本实验以东农46为研究对象,利用扫描电子显微镜技术,对大豆发育过程中根瘤、根瘤菌和淀粉粒的结构特征、形态变化进行超微结构观察.结果表明,大豆发育过程中根瘤的发育可分为三个时期,即:根瘤菌的侵入和感染;根瘤的形成和发育;根瘤及根瘤菌退化.各时期的根瘤菌经历了形态及数量发育的变化,由初期数量较少、形态不规则,到数量大幅度增加充满侵染细胞,最终随着侵染细胞开始衰亡其内部的根瘤菌逐渐减少至全部消失.

Observation of soybean nodule by scanning electron microscope

In a symbiotic system, the soybean provides the appropriate micro-environment for the growth of soybean root nodules, and in turnthe soybean nodules provide the essential nutrients of essence for the development of soybean plants. The biological nitrogen fixation ability of legume is accomplished through the infection of the root nodule bacteria. Being infect by the root nodule after the soybean root,the symbiotic nodule, which was converted to ammonia by the biological nitrogen fixatio in the air, was formed. In this study, the Dongnong46 were studied. Scanning electron microscopy was used to observe the structure and morphology of nodules, nodules and starch grains during the development of soybean. The results showed that the development of the root nodules could be divided into three stages during the development of soybean:The invasion and infection of the nodule bacteria;Formation and development of nodules;Degradation of nodules and nodules. In each period,the rhizobia experienced the changes of morphology and quality:initially, It showed less amount and irregular shape;Then the amount of it was increased and it was filled with infected cells;finally, the rhizobia gradually decreased and disappeared due to the death of infected cells.