File Catalog

ROOT SYSTEM

                It is the underground main axis of the plant body which is brown in colour developing from the embryo. Root system is of two types as follows:

Ø  Tap Root System (Found in Dicot plants)

·         The main root develops from the radicle (first part of the seed) of the germinating seed known as primary roots or tap root.

·         Later the taproot develops into lateral roots known as secondary roots bearing rootlets and root hairs known as tertiary roots(helps to absorb the water from the soil)

Examples: Maize, Carrot, Raddish, Mango etc.

Ø  Fibrous Root System (Found in Monocot plants)

·         The radicle of this is short lived and degenerates many new roots developing from the base of the stem in the form of fibres, hence known as fibrous root.

·         If the root develops from the other parts of the plant except from the radicle known as adventitious roots.

Examples; Bean, Paddy, Marigold etc.

Ø  Zones/Regions of a Typical Root

·         Root Cap Zone

§  It is cup shaped structure covered with the tip of the root.

§  The root apices are covered with root cap from from the meristematic tissue known as calyptrogen.

§  The root cap is replaced by root pockets in hydrophytes. Example: Pistia, Lemna.

§  It gives protection to the root cap.

·         Root Hair Zone

§  It is present above elongation zone.

§  It produces cluster of fine thread like structures known as root hairs.

§  Root hairs arise from the epidermal cell hence it is known as piliferous layer.

·         Elongation Zone

§  It is present above the meristamatic zone and behind the root cap.

§  In this zone newly formed cells expands and elongates linearly to increase the length of the root.

·         Maturation Zone

§  It is present above the root hair zone.

§  The tissue in this zone develops into permanent tissue.

§  In this zone secondary growth takes place along with the conduction of water and mineral salts. 

Ø  Characters

·         Root is differentiated into nodes and internodes.

·         Leaves and normal buds are absent.

·         Root apex is protected by root cap.

·         Root hairs are unicellular in nature.

·         Root grows underground in -vely geotropic (or) –vely phototropic manner. 

Ø  Functions

·         It helps in fixing the plants in the soil.

·         It helps in absorption of water and mineral salts from the soil.

·         It helps in conduction of water to the stem.

·         It stores the food materials to perform different functions.

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