Parenchyma tissues cell structure types parenchymatous cell

Definition


The simplest tissues with cells having thin and elastic walls are known as parenchyma's tissues.


Explanation


They forms the main ground tissues of plants. The are continuous throughout the body of plants. Generally, they are present in roots, stems, and leaves.

Cell Structure


The parenchymatous cells have active protoplast. They have prominent nucleus. Parenchymatous cells have thin primary and secondary elastic walls. These walls are composed up of cellulose. Parenchymatous cells are closely packed. But intracellular spaces are produced by dissolution of middle lamella. These air spaces plays very important role for gaseous exchange.

I.e.

Aerenchyma's


They have prominent intracellular spaces.


Shapes of Parenchyma cells


They have different shapes

1. Polyhedral


Mostly these cells are polyhedral in shape.

2. Stellate


These parenchymas are are present in the stems of plants. They have well developed air~spaces b/w them.

3. Elongated


They are found in the palisade tissue of leaf.

4. Lobed


Lobed parenchymas are found in spongy.


Origin of parenchyma


Mostly, parenchyma are primary in origin.  But sometimes, they are also produced as a result of secondary growth.

Functions and types of parenchyma


Parenchyma cells are less specialized, But it performs major/important activities in the plant cell.

1. Meristematic


They resume meristematic activity during some special conditions. These conditions are regeneration, wound healing, union of grafts, formation of adventitious roots.

2. Photosynthesis


Some parenchyma are involved in photosynthesis.

Assimilatory parenchyma or chlorenchyma


The parenchyma cells of mesophyll tissues of leaves are rich in chloroplast. They are called chlorenchyma or A.P.

3. Storage


Some parenchyma also store food in fruits and roots etc. They are known as storage parenchyma. Storage parenchyma are common in the cortex of stem, roots and seeds.

4. Ground tissues


Parenchyma acts as ground tissue mostly.

5. Excretoty structure


In some casea, parenchyma act as a excretoty structure.

6. Pigmented cells


Flowers and fruits cells of parenchyma contains chromoplast. It give colours to fruits and petals.

7. Storage of Water


Some parenchymas have ability to store water. I.e cells of succulent plants store water.

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