Have you ever propagated a geranium plant by cutting it? You take a small stem on which a few leaves are growing and keep it well watered. When a few tiny foots begin to appear, you plant the stem in soil. After a few weeks, the cutting grows roots, which are just like the roots of the original plant. The new plant has the hereditary traits of the parent plant.
Many plants and shrubs are propagated this way. In each case, the new plants are just like the parent plants because in each cell there is a mechanism that operates to maintain the hereditary pattern from one cell to its daughter cells. The process by which this occurs is known as cell division, or mitosis. The following eight slides were photographed from a single onion root tip showing the phases of plant mitosis in sequence. The terms ” equatorial plate” and ” poles,” as they are used in the study of mitosis, refer to certain locations in the cell. The equatorial plate in these slides runs from the left side of the slide to the right; the poles are locations above and below the equatorial plate.