How parenchyma, sclrenchyma and collnchyma?

Asked by  | 22nd Sep, 2012, 07:40: AM

Expert Answer:

The figures of parenchyma, collenchyma and sclerenchyma are given in NCERT book, Figure 6.4 a(i), b(i) and c(i)
Parenchyma - It consists of relatively unspecialised living cells with thin cell walls. They are loosely packed with large intercellular spaces. This tissue provides support to plants and also stores food.
When it contains chlorophyll and performs photosynthesis, this tissue is called chlorenchyma.
Large air cavities are present in parenchyma in some aquatic plants to give buoyancy to the plants and help them float. Such a parenchyma type is called aerenchyma.
Collenchyma – The cells of collenchymas are living, elongated and irregularly thickened at the corners, with very little intercellular space. Collenchyma provides flexibility in plants. It allows easy bending in various parts of a plant such as leaf and stem without breaking. It also provides mechanical support to plants.
Sclerenchyma - The cells of this tissue are dead. They are long and narrow with lignified walls. Often these walls are so thick that there is no internal space inside the cell. This tissue makes the plant hard and stiff. This tissue is present in stems, around vascular bundles, in the veins of leaves and in the hard covering of seeds and nuts. It provides strength to the plant parts.

Answered by  | 24th Sep, 2012, 08:14: AM

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