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The tissue which makes the plant hard and stiff and provides strength to the plant parts is the:
sclerenchyma
chlorenchyma
aerenchyma
collenchyma
sclerenchyma
Sclerenchyma is a simple, permanent plant tissue consisting of dead cells with highly thickened, lignified cell walls. Its primary function is to provide mechanical strength, rigidity, and hardness to various plant parts.
Sclerenchyma is a simple, permanent plant tissue consisting of dead cells with highly thickened, lignified cell walls. Its primary function is to provide mechanical strength, rigidity, and hardness to various plant parts.
Think of sclerenchyma as the reinforced concrete pillars in a building; just as concrete provides the rigid structure to keep a high-rise standing, the lignified walls of sclerenchyma provide the internal support system for mature plant stems and protective layers.
S-S-S: Sclerenchyma = Strength, Stiffness, Secondary walls.
Secondary┬аWall=Primary┬аWall+Lignin
Mechanical┬аStabilityтИЭLignin┬аContent
The strength of sclerenchyma arises from the deposition of lignin, a complex polymer, within its secondary cell walls. The cells are typically elongated (fibers) or spherical (sclereids), and their maturity involves the death of the protoplast, leaving a hollow, rigid structure that acts as a structural skeletal system for the plant.
Sclerenchyma cells are dead at maturity.
The cell walls are thick and lignified.
It is found in stems, around vascular bundles, and in the hard shells of seeds/nuts.
It provides structural support without elasticity.
Provides extreme rigidity and mechanical support.
Protects delicate internal plant tissues.
Lacks flexibility; can fracture under extreme stress compared to collenchyma.
Found in the hard shells of walnuts and coconut husks.
Forms the hard outer covering of seeds and specialized tissues in vascular bundles.
| Feature | Sclerenchyma | Collenchyma |
|---|---|---|
Cell Wall Type | Thick & Lignified | Thin/Unevenly thick |
Lignin is a water-repellent (hydrophobic) substance, which also prevents decay in mature tissues.
Option B (Chlorenchyma) is parenchyma with chloroplasts for photosynthesis. Option C (Aerenchyma) is parenchyma with air spaces for buoyancy. Option D (Collenchyma) provides flexible mechanical support, not rigid hardness.
A is correct тАФ Sclerenchyma is the specific plant tissue characterized by thick, lignified walls that provide hardness and structural strength.
Remember: Collenchyma for 'Flexibility' (C for C, like a curved plant stem) and Sclerenchyma for 'Stiffness' (S for S, like a hard seed shell).
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