[Demonstrating the localization of hemoproteins by an electron cytochemical method]

The dynamics of division and interphase cell size in the growing ovule of Pinus silvestris was studied on histological slides in the year of fertilization. A constant extension in size of dividing cells of the endosperm was shown which, in this respect, do not differ much from the interphase ones. Cell division and elongation in this tissue occur simultaneously to be completed only with the transition of cell to differentiation. The size extention of the dividing cell does not influence the frequency of cell division. In the integument and the nucleus, the value of dividing cells is relatively constant. At the transition of these cells to elongation their mitotic activity decreases shaply to stop completely after-wards. Cell division and elongation are divided here in time.