Periclinal division of cambium

In the top transmission electron micrograph is a transverse sectional view of a cambial cell in elm (Ulmus sp.) at the telophase stage of mitosis. Shown is the initiation of the cell plate during periclinal division of a fusiform cell. Sister nuclei did not get into this section because fusiform initials are very elongated cells and the chances to cut nuclei during cross sectioning are low.

At the bottom, is a more detailed view of growing cell plate (the growth occurs by way of lateral fusion of secretory Golgi vesicles). Also seen are microtubules of the phragmoplast aligning perpendicularly to the cell plate.