Science Articles

Structure and Function of Plant Roots

What do you see when you look around you? You see people, roads, cars and of course, trees and plants.
Plants are the second largest kingdom of living things after animals. All plants have certain distinct features that distinguish them from animals.

What do you see when you look around you? You see people, roads, cars and of course, trees and plants.
Plants are the second largest kingdom of living things after animals. All plants have certain distinct features that distinguish them from animals.

Plants have two main parts- the roots and the shoots. The shoots are the part of the plant above the ground, while the roots are those parts of the plant that are below the ground.
Here, we will go into the depth of roots ad understand their functions, structure, types and modifications.

Functions of Roots-
Roots play a very important role in the life of a plant. They have two very major functions that are crucial to the plant-
1. Roots help to fix the plant firmly in the ground, thus lending them support and strength.
2. Roots absorb nutrients, water and minerals from the soil and conduct them to the stem. Thus, they play a crucial role in the nutrition of a plant.

Root Systems-
Plants generally display two kinds of root systems-
• Tap Root System
• Fibrous Root System

Tap Root System-
Some plants have a single, main root that comes out of the seed after germination. This single root is called as the primary root. The primary root is distinguished by its thick, long structure. Small root branches sprout from this primary root. These branches are known as secondary roots. This kind of root system is known as Tap root system. It can be seen in plants such as peas, beans and gram plants.

Fibrous Root System-
Some plants do not display primary or secondary roots. The roots are all of the same length, size and thickness. The roots grow from the base of the stem, and display a bushy appearance. This kind of a root system is known as Fibrous root system. It can be seen in plants such as rice, wheat, maize and lily.

Modifications in Roots-
In some plants, the roots are modified to fulfil certain functions for the plant. These are called modified roots or special roots. Some of these are-

1. Storage Roots-
Roots of some plants store a large quantity of food for the plant. They therefore appear thick and swollen. Carrots, beetroots and radishes have a tap root system, where the primary root is modified to store food. Sweet potatoes have a fibrous root system, where the fibrous roots are modified to store food.

2. Support Roots-
Some trees have roots that come out from the upper branches of the tree and grow downwards to reach the soil, instead of the conventional upward movement of roots. These downward growing roots provide additional support to the tree. Such roots are called prop roots are generally present in trees that are wide and have a large girth, for example, banyan tree.

3. Stilt Roots-
In some plants, specialised roots called stilt roots grow form the lower side of the stem in order to provide additional support to the plants. Such roots are generally seen in plants that have a tall and weak stem, for example, sugarcane plant.

4. Climbing Roots-
Some plants display specialised roots that attach themselves to a support and help the plant to grow upwards. Such specialised roots are called as climbing roots and are generally seen in plants that have a weak stem, for example, in plants such as money plant and black pepper plant.

5. Breathing Roots-
In coastal areas, the soil is mostly covered with salty sea water due to which the roots of coastal plants do not get enough oxygen. In such areas, plants display roots that grow out of the ground and rise upwards like spikes. These spikes absorb oxygen from the air. These spike-like roots are known as breathing roots.