Modifications of Roots - ep2

Root modification occurs when plant roots adapt to perform extra functions beyond normal requirements to fulfill the plant's needs. Roots can modify for four major purposes: food storage, mechanical support, gaseous exchange, and other vital functions.

Roots for mechanical support

• Prop roots grow vertically downward from the horizontal branches of a banyan tree into the soil to hold up its massive weight.
• Stilt roots are adventitious roots that grow out from the nodes of sugarcane to keep the plant firmly supported as it grows.
• Climbing roots grow at the nodes and internodes of the betel plant to anchor and support its climbing stem.

Roots for gaseous exchange

Gaseous exchange does not take place only in leaves, as certain plant roots also exchange gases with the atmosphere. In mangrove forests, where the soil is in very bad condition, trees like Avicennia develop breathing roots known as pneumatophores. These roots stick straight up out of the soil like small sticks to take in carbon dioxide and release oxygen. This adaptation allows the tree to breathe and survive in harsh swamp environments.

Roots for vital parasitic functions

• Parasitic organisms survive by depending completely on another living organism for their basic needs.
• A parasitic plant such as Cuscuta wraps itself around a host tree instead of living independently.
• Cuscuta develops specialized sucking roots called haustoria that reach into the host tree.
• These haustoria absorb all the necessary nutrients and energy directly from the host tree.

Roots for food storage

Plants also modify their root systems to store reserve food for later use. A carrot is a modified root rather than a fruit or vegetable, functioning to store nutrients for the plant. Roots that modify for food storage can be differentiated from one another by their distinctive physical shapes. This stored energy helps the plant sustain itself over time.