Root - Tap Root Modifications

Description:

Tap root undergo modifications in order to perform additional function like storage, respiration, vegetative propagation etc. The modifications are −

Storage roots

• Modified for storage of food.
• Primary root gets swollen and food is stored in it.
• The various forms of stored roots are −

  • Conical Base of the root is broad and gradually tapers towards the apex. E.g. Carrot.

  • Fusiform Root is swollen in the middle and tapers at both the ends. E.g. Radish.

  • Napiform Thickest at the base and takes spherical shape. It suddenly tapers at the apex. E.g. Beet

Nodulated roots

• Small nodule like swellings may occur in primary, secondary and tertiary roots.
• These nodules bear nitrogen fixing bacteria which can convert atmospheric nitrogen into forms which can be used by plants.

Pneumatophores

• Also called respiratory roots.
• Found in plants growing in mangroves or swamps near sea shore.
• These roots arise vertically upwards and come out of soil and water.
• They bear small pores called pneumathodes or lenticels for the exchange of gases.