Sclerenchyma: (Gk; Sclerous: hard; enchyma: infusion)
• Non-living mechanical tissue
• Thick walled, lignified and pitted
cells without protoplasm at maturity
• Distribution: cortex, hypodermis,
vascular regions of stem, leaves, fruit wall etc
1. Sclerenchyma
Fibres
- Thick, elongated, spindle shaped cells with pointed tips.
- Narrow lumen with simple rounded pits and lignified secondary wall
- Distribution: cortex, pericycle, xylem and phloem
- a. Surface fibres: found on fruit wall and seed coat (e.g., coconut)
- b. Xylary or Wood fibres: associated with xylem
- c. Extraxylary or Bast fibres: seen associated with cortex, pericycle and phloem
- Provide mechanical support to the plant parts
- Surface fibres help in seed and fruit dispersal
2. Sclereids

• Small sclerenchymatous cells with highly thickened lignified walls and narrow lumen.
Distribution: pulp of fruits, fruit walls, cortex, pith etc
Different types of Sclereids
• a. Brachysclereids: isodiametric sclerieds called as
stone cells
Grit cells: Numerous Stone cells present in the pulp of fruits (guava,
sapota)
Distribution: cortex, pith, pericarp of coconut shell
• b. Macrosclereids: rod like sclerieds- present in bark
and seed coat of leguminous plants
• c. Osteosclerieds: Bone like sclerieds with lobed
ends-seed coat and fruit wall
• d. Astrosclereids: star shaped sclerieds- dicot leaves
and gymnosperms
Functions of Scelrenchyma
- Dead mechanical tissue providing strength and support to the plant
- Protects from damages
- Xylem fibres in water conduction
- Fibrous sclerenchyma of fruits and seeds helps in seed dispersal.
Tags:
Fibres different types
Fibres vs Sclereids
Permanent Tissues
Sclereids different types
Sclerenchyma
Sclerenchyma function