Theory:

 
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Longitudinal and cross sections of simple permanent tissues
Differences between Parenchyma and Collenchyma:
Features
Parenchyma
Collenchyma
Cell wall
It is a living tissue contains a thin cell wall made up ofcellulose.
It is a living tissue consists of a thick cell wall made up of cellulose, pectin, and hemicellulose.
Arrangement of cells
Cells areloosely arranged with intercellular spaces, and their thickness is uniform.
The tissue consists of uneven well-developed thickenings at places adjacent to intercellular spaces.
Function
It helps in the storage of food, nutrients and water.
Being a mechanical tissue gives flexibility and elasticity to the plant and prevents leaves' tearing.
Location
It is present in the inner and outer parts of plant organs.
It is located mainly in the arial parts of the plant. It is restricted to sub epidermal parts of the plant.
Differences between Collenchyma and Sclerenchyma:
Features
Collenchyma
Sclerenchyma
Nature of cells
Cells are living.
Cells are dead.
Cells are made up of
Cells contains protoplasm (It has a central vacuole and peripheral cytoplasm with an elongated nucleus).
Cells are empty.
Intercellular spaces and lumen
Intercellular spaces are absent, and the lumen of the cell is wide.
Intercellular spaces are absent, and the lumen of the cell is narrow.
Thickening of cell wall
It consists of an uneven thickening cell wall is made up of cellulose.
It consists of a uniform thickening cell wall, which is lignified.
Pits
Pits are simple straight, and unbranched.
Pits are simple oblique; sometimes, they are branched.
Function
Being a mechanical tissue gives flexibility and elasticity to the plant and prevents leaves tearing.
It helps to provide mechanical support to the plant.
Difference between Sclereids and Fibres:
Features
Sclereids
Fibres
Shape of cells
They are short and broad irregular shaped branched/unbranched cells with blunt end walls.
They are elongated and narrow thread-like unbranched cells with tapering end walls.
Arrangement of cells
Generally occur singly or in groups.
Generally occur in bundles.
Pits
Pits are deep.
Pits are narrow.
Function
It provides grittiness to fleshy fruits and stiffness and hardness to nuts and seed coat.
It provides strength and hardness.
Origin
It is derived from a secondary wall thickening of parenchyma cells.
It is directly derived from the meristematic tissue.