• The parts of the plant that anchor plant to the ground and remain under the ground (roots) form the root system.
• Root systems are mainly of two types:
Tap root system:
• In the tap root system, a single root (called the primary root) comes out from the seed after germination.
• Tap roots are also called true roots.
• Later, smaller roots called lateral roots branch out from this primary root.
• Mango, Neem, Pine, Sheesham, Pea, Carrot, Radish, Turnip, and Beetroot are examples of plants in which tap roots are found.
Fibrous root system:
• Fibrous roots grow from the base of the stem, and have a bushy appearance.
• These roots are thin and almost equal in size.
• Grass, Maize, Wheat, Onion, Sugarcane, and Rice are examples of plants in which fibrous roots are found.
Functions of Roots:
i. Anchorage – Roots anchor the plant firmly to the soil (mechanical function).
Roots anchor the plant firmly to the soil and absorb water and mineral salts from the soil
ii. Absorption – Roots absorb water and mineral salts and conduct them upwards (physiological function).
iii. Special functions – By undergoing modifications in their structure, roots perform special physiological functions like:
• Food storage
• Absorption of atmospheric moisture
• Sucking food from host plant
• Gaseous exchange
• Roots of some plants are modified to perform additional functions.
• For storage of food, the roots of some plants, such as radish, carrot, turnip, sweet potato, and beetroot, store food and become fleshy.
• For climbing, some plants have climbing roots that help the plant to climb up a support such as a wall, rock, or tree, e.g., money plant, black pepper, and betel.
• For nutrition, plants such as dodder have specialized roots called parasitic roots arising from their stem, which help them to absorb water and nutrients from the host.
• Roots of plants such as dahlia and asparagus can develop into new plants.
• For extra support, root of plants such as Bamboo, Sugarcane, and Banyan give out additional roots from their branches.
• These roots grow downwards and give extra support to the stem of the plant. These are called prop roots.
• The great Banyan tree in Sibpur, Kolkata is more than 200 years old, forming a crown of over 404 metres in circumference and has about 1600 prop roots.