Modifications of Tap and Adventitious Roots

Root is a part of a plant which develops from radicle and grow towards the soil. There are two types of roots. Tap roots and adventitious roots. The main functions of roots are absorption, conduction and fixation. But roots are modified to perform different functions according to habitat. The modifications in roots are as follows:-

Modifications of tap roots

Tap root is developed from radicle and grow towards the soil. It is deeper and found in dicot plants. Tap roots are modified to perform the following functions:-
1. For storage of food 2. For respiration

For storage of food:
In this type of modification the tap root becomes swollen and fleshy due to food storage. There the mainly three types of modification for food storage:-

Fusiform: When the root is swollen in middle and gradually tapering towards the apex , it is called fusiform root. E.g. Radish (Raphanus sativus)

Conical form: When the root is broad at the base and gradually tapers towards the apex like a cone, it is known as conical form root. E.g. Carrot (Daucus carota)

Napiform: When root is considerably swollen at the upper part and becoming sharply tapering at the lower part, it is called napiform root. E.g. Turnip (Brassica rapa)

For respiration:
Many plant s grow in the swamps and marsh areas where oxygen is found in less quantity. To get oxygen and helps in respiration this type of root modified. Pneumatophores are developed in this root which helps in gaseous exchange. Eg. Rhizophora.

Modifications of adventitious roots

Adventitious roots are not developed from radicle but these types of roots are developed from other parts of the plants. The main reasons of modifications in adventitious roots are :

Food Storage
Mechanical support
To Carry out special functions

For food storage:
Adventitious roots also modified for food storage. The main types of roots are:-

Fasciculated roots : The roots of some plant take the form of clusters for food storage. Eg. Dahlia

Nodulose roots: When the roots become swollen near the tips, they are said to be nodulose roots. E.g. Amaheldi

Tuberous roots: These types of roots swollen and do not get definite shape. E.g. Sweet potato.

Moniliform: In certain roots, the swelling occurs at regular intervals. E. g. Grapes.

Annulated: In this type of modification roots possess a series of ring like out growth on its body. E.g. Ipecac, Cinchona

For Mechanical Support:-
These types of roots provide mechanical support to plants. The main types of modifications are:-

Prop roots: The main example of prop root is Banyan tree. These roots arise from horizontal branches and grow vertically downwards and penetrate into the soil.

Stilt roots : These types of roots arise from lower internodes of a weak stem. These roots penetrate obliquely in soil and provide mechanical support to the plant.

buttress roots : These roots are helpful in fixing the plant at its normal position. E.g. Semal Prombab malabaricum

Climbing roots : These types of roots are found in climbing plant and help in climbing .E.g. Money plant.

Hanging roots : This type of roots help in fixing the plants to the supporting host. E. g. Vanda

To Carry Special Functions:
Some roots are modified to perform special functions. Some important types are given below:

Absorbing roots :- some plants are epiphytes. These type of roots help in absorption of atmospheric moisture. E.g. Vanilla

Assimilatory roots:- These types are roots have chlorophyll and prepare food for the plants. E.g. Tinospora

Sucking roots: These types of roots are found in parasitic plant and help in absorption of food from host. E.g. Cuscuta

Reproductive roots: Some roots help in reproduction, hence called reproductive roots. E.g. Sweet potato

Mycorrhizal roots:- There is beneficial mutual partnership between a fungus and a root. So it is type of symbiosis. E.g. Pinus and Monotropa

Floating roots: These type of roots are found in aquatic plants and help in floating. E.g. Jussiaea

Contractile roots:- In underground stem of some plants like Onion , Garlic etc some roots are thick and fleshy. Their apical part contracts and fixes the plant in the soil.

Nodulated roots: These are also the examples of symbiosis in which Bacteria are found in the root nodules of Leguminous plants. E.g. pulses, Ground nut, etc.

So These are the modification of tap and adventitious roots. I think this article will be helpful to all the students of biology group. I have explained the modification in very easy language.

Modifications of Tap and Adventitious Roots

Modifications of tap roots

Modifications of adventitious roots

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