Microtubule dynamics in mitosis & cytokinesis

A Interphase: Cortical microtubules are aligned within the inside of the cell wall.

B Pre-prophase: Microtubules form a band around the equatorial region of the cell marking the plane of future cytokinesis.

C Prophase: Cytoplasmic microtubules disappear and a mitotic spindle of microtubules is formed.

D Metaphase: Chromosomes are aligned on an equatorial plate of the spindle.

E Anaphase: Interzonal fibers extend from one pole to the other. Chromatids are moved to opposite poles of the spindle. Dictyosomes (two are shown) begin to produce vesicles which will fuse laterally initiating the cell plate.

F Telophase: The spindle microtubules disappear and a phragmoplast is formed whose component microtubules are concentrated at the periphery of the cell plate which grows centrifugally towards the parent cell wall. The phragmoplast microtubules remain at the edge of the cell plate until it reaches the parent cell wall, and then they disappear.

 

Illustration from: Ledbetter & Porter, 1970, Introduction to the Fine Structure of Plant Cells, Springer-Verlag