What happens in apical meristems at the tips of roots and shoots?

Apical meristems are regions of actively dividing cells located at the tips of roots and shoots, serving as the primary centers for plant growth and development. Because these cells undergo unlimited division throughout a plant's life, they are responsible for the extension of the primary plant body.12

Cellular Activity and Differentiation

The cells within these meristems are typically small and nearly spherical, characterized by dense cytoplasm and few vacuoles. Within these regions, specific cells known as initials undergo mitosis to maintain a constant supply of new cells. These cells eventually differentiate into three primary meristems that form the plant's tissues:12
* Protoderm: Develops into the epidermis.
* Ground meristem: Forms ground tissues, including parenchyma, collenchyma, and sclerenchyma.
* Procambium: Gives rise to vascular tissues, specifically xylem and phloem.

Root vs. Shoot Meristems

• Root Apical Meristem: Located at the root tip, this region is protected by a root cap, which is continuously replenished by a layer of cells called the calyptrogen. Growth here follows distinct zones: cell division, cell elongation, and tissue maturation.13
• Shoot Apical Meristem: These centers produce leaves and buds that can develop into branches. Unlike roots, shoot meristems are responsible for the exogenous origin of these structures.13