Meristematic tissue: apical, lateral, intercalary

1. Introduction to Plant Tissues

  1. A tissue is a group of cells with a common origin and function.
  2. Plant tissues are classified into meristematic and permanent tissues.
  3. Meristematic tissue consists of actively dividing cells responsible for plant growth.

2. Characteristics of Meristematic Tissue

  1. Cells are small, thin-walled, and compactly arranged.
  2. Large nucleus present with dense cytoplasm.
  3. Cells lack vacuoles (since they do not store food or water).
  4. Responsible for primary and secondary growth in plants.

3. Types of Meristematic Tissue

  1. Based on their position in the plant body, meristematic tissues are classified into:

a) Apical Meristem

  1. Found at the tips of roots and shoots.
  2. Responsible for primary growth, increasing the length of the plant.
  3. Divided into:
    • Protoderm – Forms the epidermis.
    • Procambium – Develops into vascular tissues (xylem and phloem).
    • Ground meristem – Forms ground tissues like cortex and pith.

b) Lateral Meristem

  1. Located in the cambium region (vascular and cork cambium).
  2. Responsible for secondary growth, increasing the girth (thickness) of stems and roots.
  3. Examples:
    • Vascular cambium – Produces secondary xylem and phloem.
    • Cork cambium – Produces protective bark tissues.

c) Intercalary Meristem

  1. Present at the base of leaves, nodes, and internodes.
  2. Found mainly in monocots (e.g., grasses, bamboo).
  3. Helps in regrowth of grasses after grazing or cutting.

4. Functions of Meristematic Tissue

  1. Growth: Increases plant height and width.
  2. Formation of new cells: Produces primary tissues.
  3. Healing: Helps in wound healing and regeneration.
  4. Branching: Responsible for shoot and root branching.

5. Differences Between Meristematic and Permanent Tissue

Meristematic TissuePermanent Tissue
Cells are actively dividing.Cells have stopped dividing.
Cells have thin walls.Cells may have thick walls (e.g., sclerenchyma).
No vacuoles present.Vacuoles are present for storage.
Helps in growth and development.Performs specialized functions (e.g., support, transport).

6. Importance of Meristematic Tissue

  1. Essential for growth and plant development.
  2. Plays a crucial role in wound healing and regeneration.
  3. Provides cells for the formation of permanent tissues.
  4. Enables plants to adapt to environmental changes.

7. Conclusion

  1. Meristematic tissue is vital for plant growth and differentiation.
  2. Its different types (apical, lateral, intercalary) perform specific functions.
  3. Understanding meristematic tissue helps in botany, agriculture, and forestry.
Category
Tissues and Tissue Systems
Plant Anatomy
Botany