Cytological studies on the root nodules of pea

Abstract

The material used in this investigation is the root nodules of pea (Pisum sativam), which was fixed in Bouin's fluid, imbedded in paraffin, sectioned at thicknesses of 10-13μ and stained in Heidenhain's iron-alum-haematoxylin. According to this investigation, mitosis have been odserved during the meristematic region and amitosis during the early development of the bacteroid tissue. At the beginning of the am itosis, the nucleolus is gradually developed and becomes somewhat oval in shape (Fig. 2), and later, a constriction appears in the centre of nucleolus. At about the same time a constriction appears in the nucleoli (Fig. 3, 4) to separate them in two daughter nucleoli (Fig. 5, 6). In the bacteroid tissue, the nucleolus of almost every cell shows a small spherical bud which can be stained as deeply as the nucleolus itself. The amitosis and the buddings of nucleoli, which occur in the cells of the bacteroid tissue indicate some particular conditions in the cell. The chromosome numbers in meristematic region of the root-nodule of pea is 28, although 14 in foot tip cell.