1.1 Plant Tissues

Definition of Tissue

• A group of similar cells that work together to perform a specific function.

Classification of Plant Tissues

1. Meristematic Tissues: Actively dividing cells, responsible for growth.
2. Permanent Tissues: Cells that have lost the ability to divide, with specific shapes, sizes, and functions.

Meristematic Tissues

• Characteristics: Small, isodiametric, compactly arranged cells with dense cytoplasm, large nucleus, thin cell walls; actively dividing.
• Location: Growing regions (root tips, shoot tips, cambium).
• Function: Responsible for plant growth in length and girth.
• Examples: Apical meristem, Lateral meristem, Intercalary meristem.

Simple Permanent Tissues

• Made up of only one type of cell.
• Parenchyma:
  • Structure: Thin-walled, isodiametric cells with large vacuoles and intercellular spaces.
  • Functions: Food storage, photosynthesis (chlorenchyma), turgidity.
• Collenchyma:
  • Structure: Elongated cells with unevenly thickened cell walls.
  • Functions: Mechanical support and flexibility to young stems and petioles.
• Sclerenchyma:
  • Structure: Long, narrow, thick-walled, lignified, dead cells.
  • Functions: Mechanical strength and rigidity.

Complex Permanent Tissues

• Made up of more than one type of cell, working together as a unit.
• Xylem:
  • Function: Transport of water and minerals from roots to other parts of the plant.
• Phloem:
  • Function: Transport of food (sugars) from the leaves to other parts of the plant.