Collenchyma tissue Cell structure

The parenchyma cells with uneven angular thickening which support young growing part of plant are called collenchyma.

parenchyma

Cell structure and organization


These cells have living protoplast. They are simple tissues & contain single type of cells. Collenchyma cells have pointed & prismatic elongated end tips. They provide further growth and divisions. Collenchyma tissue also contains chloroplasts in green organs.

Presence


Collenchyma tissue are present in the margin of leaves.

Presence of cell wall in collenchymatous cells


Thickened primary wall is non-lignified. Mostly, it is composed of cellulose. Therefore, it shows elasticity in nature. The angular thickening are rich in cellulose. Additional layer of microfibrils is also present inside the wall.

Sclerification


In some cases, the cell wall of Collenchyma is sclerified. Sclerification occur by the formation of lamella. The lamella is rich in cellulose.

Size and shapes


Different collenchyma tissues have different sizes and shapes. Mostly, these cells are elongated with tapering ends. The largest type of Collenchyma tissues are present in the central position. In the periphery, shorter collenchyma tissues are present.

Types of Collenchyma tissue


1. Angular collenchyma


Angular collenchyma are present in the petioles of some plants.

2. Lamellar collenchyma


These collenchymatous cells are present in the stem cortex of some plants.

3. Lacunar collenchyma


They are present in the petiole of composite species.

Types of Collenchyma tissues

Functions of Collenchyma tissue


1. Elasticity


It has elasticity. So they provide mechanical support to plants.

2. Support


Collenchyma tissue are present in herbaceous plants. And provide support to such weak plants.

3. Photosynthesis


Some collenchyma contains chloroplast. So they are called photosynthetic.

4. Support to leaf


They are present around the vascular bundle of leaf. So they provide support to leaf tissues.

5. Bundle sheath and bundle caps


They form bundle caps and bundle sheath in leaves.

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