Abstract
The material used in this investigation is the root nodules of soy bean, which were fixed in Bouin's solution and stained in Haidenhain's iron-alum-haematoxylin. Sections were cut at 7-10μ. According to this investigation, amitosis have been observed during the early development of the bacteroid tissue. At the beginning of the amitosis, there appears small chromatin granule at one point of the nucleolus (Fig. I). And secondary nucleolus is gradually developed from the chromatin granule separating from the original one (Figs. 2, 3 and 4). At about the same time, the nucleus becomes somewhat oval in shape (Fig. 4), and later, a constriction appears in the centre of those two nucleoli (Figs. 5 and 6) to separate them into two daughter nuclei (Fig. 7). MILOVIDOV (1926) has distinguished following three types of root nodules with respect to the mode of infection. (a) Normal type : infection takes place by aid of intracellular infection threads. (b) Type in Serradella : Infection takes place by aid of intercellular infection threads. (c) Type in Lupinus : Infection takes place by aid of mitotic cell divisions. It is desirable for me to add one more type, namely, type in soy bean in which infection takes place by aid of amitotic cell divisions.
