Collenchyma Tissues in Plants

Collenchyma Tissues

• Collenchyma is a simple, permanent tissue found in shoots and leaves of plants.
• Collenchyma cell walls are thickened with cellulose.
• Thickening mainly occurs at the corners.
• This tissue provides strength, especially in growing shoots and leaves.
• Cells are tightly packed, with fewer intercellular spaces.

Characteristics of Collenchyma

• Typically located between the stem's cortex and vascular bundles' endodermis.
• Consists of living cells.
• Cell shapes are elongated, oval, spherical, or polygonal.
• Cells have unevenly thickened primary cell walls.

Additional Collenchyma Characteristics

• Intercellular spaces are small.
• Collenchyma can expand in radial and tangential directions due to weak lignified cell walls.
• Contains chloroplasts for food storage.
• Gets crushed during secondary plant growth.

Types of Collenchyma

• Based on cell wall thickening patterns:
  • Angular collenchyma: Uniformly thickened corners. Most common type.
  • Annular collenchyma: Uniformly thickened cell walls.
  • Lamellar collenchyma: Unevenly thickened, with continuous layers.
  • Lacunar collenchyma: Thickening concentrated around intercellular spaces.

Collenchyma Structure and Function

• Structure: Cells are typically spherical, oval or polygonal, with minimal intercellular spaces. Cell corners are thickened with cellulose and pectin. Most cell walls are thin.
• Function: Close packing for structural support. Thickened corners offer mechanical strength. Thin walls allow for flexibility.

Functions of Collenchyma

• Provides structural support, acting like an internal framework similar to bones.
• Protects the plant from damage caused by stresses (rain, wind).
• Supports growing areas (shoots, leaves).
• Fills vacant areas to be used for later growth.