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Meristems and Mitotic Cell Divisions
Meristems are the specific sites in the plant where mitotic divisions produce new cells. Most plants grow from the tips of branches and roots where apical meristems produce new cells. As a result, in all buds, at the ends of all branch tips and on root tips, apical meristems are found.
Apical meristems produce new cells that differentiate into three distinct embryonic tissues. These are the protoderm, ground meristem, and procambium. In the diagram, you can see protoderm will form the epidermal tissues. Ground meristem is the embryonic tissue that forms cells of the cortex and pith. Procambium forms the vascular tissues, xylem and phloem. Apical meristems contribute to initial plant growth called primary growth.
In stems and roots of woody plants, the procambium can persist to eventually form a continuous ring of meristematic tissue called the vascular cambium. This is the layer that produces new phloem and xylem tissues yearly, contributing to growth rings visible in woody plants. A second ring of meristematic tissue forms just below the epidermis in woody plants to produce bark. This is the cork cambium. The cork cambium and vascular cambium contribute to subsequent or secondary growth typically found only in woody plants
Now, roll over the apical meristem on the diagram..
