Cell Size in Developing Ovaries of Iris fulva

Abstract

Relative growth of structure and its component cells was studied for the ovary wall at the midrib, septum, and widest radius and for the region of the septum between the locules. During much of development, growth of these regions is due to both cell division and cell enlargement. During meiosis of the megasporocyte it is due solely to increase in cell number. After fertilization, cell division has practically ceased in all regions of the wall, and further growth is due solely to cell enlargement; but division and cell enlargement both occur in the regions between the locules. The cells of one region frequently enlarge at a different rate from those of another region, but the relative growth rate which is established at the beginning of development is maintained unchanged throughout. Therefore, differences in the relative growth of two regions are due to differences in the extent of cell division in those regions.