Merisztíma

Merisztíma is a term used in plant biology to describe undifferentiated plant tissue that is capable of active cell division. This tissue is responsible for the growth and development of plants. Meristematic tissues are found in specific regions of the plant, such as at the tips of roots and shoots, and in the vascular cambium. The cells within meristematic tissue are typically small, thin-walled, and have large nuclei and dense cytoplasm. They lack large vacuoles and intercellular spaces, which are characteristic of mature plant cells.

There are two main types of meristems: apical meristems and lateral meristems. Apical meristems are located at the apex, or tip, of the plant's roots and shoots. They are responsible for primary growth, which increases the length of the plant. This includes the formation of new leaves, flowers, and roots. Lateral meristems, such as the vascular cambium and cork cambium, are found running parallel to the length of stems and roots. They are responsible for secondary growth, which increases the diameter or girth of the plant. This allows for the production of wood and bark in woody plants.

The activity of meristematic tissue is influenced by various environmental factors, including light, temperature, and the availability of water and nutrients. Hormones, such as auxins and gibberellins, also play a crucial role in regulating meristematic cell division and differentiation. The controlled activity of meristems is essential for the plant's ability to adapt to its environment, respond to stimuli, and reproduce.