The Root system || Morphology of plant root || By neettyari

The Root System of plant

The root is non-green, cylindrical, descending axis of the plant that normally grows downwards into the soil. It develop from the radicle and is the first structure that comes our when a seed is places in the soil. The direct prolongation of the radicle forms the primary root. When the primary root persists and continues to grow, as in dicotyledons, it forms the main root of the plant and called tap root.

The Root System of a Plant

Characteristic of the Root

There are certain characteristics features of the root which distinguish it form the stem.

1) The root is the descending portion of the plant axis and is usually devoid of chlorophyll containing cells.

2) Normally, it does not bear buds, but in some plants like sweet potato and wood apple roots bear buds which help in Vegetative propagation.

3) It ends in and is protected by a cap or thimble known as root cap.

4) It bears unicellular root hairs, which occur in a cluster in the younger part of the root, a little behind the apex. It absorbs water and minerals salts from the soil.

5) It is not differentiated into nodes and internodes.

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Function of Root

The cells that make up a root system have to carry out a variety of functions, and several different types of cell have  evolved for this purpose. The main function of root are as follows :

1) Absorption of water and minerals from the soil.

2) They anchor and stabilise the plant to allow for the effective functioning of the photosynthetic system.

3) They are flexible and able to withstand the strong pulling forces exertre when the wind blows without snapping and destroying the plant.

4) In some plants, roots form the means by which the plant stores the food it needs over winter.

5) In some plants, roots form a means by which the plants reproduces.

Parts of a Typical Root

The following regions may be distinguished in a root starting from the apex upword . But there is no clear cut line of demarcation between these regions and one region merges with the other.

Root cap

The root is covered at the apex by a cap or thimble- like structure called root cap. The root cap protects the tender apex of the root as it makes its way through the spoil.

Zone of cell division or meristematic zone

This is the growing apex of the root which lies within but a little beyond the root cap. It is only a few  millimetres in length. The cells of this zone are in active state of division and continuously increase in number. These cells are thin walled with dense cytoplasm and large nuclei.

Zone of cell elongation

This zone is situated just above the meristematic zone. The cells of this zone undergo rapid elongation and enlargement, and they are responsible for the growth of the root in length.

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