Modification of Adventitious Roots

Modifications of Adventitious Roots occur due to various reasons related to the plant’s adaptation to its environment and specific functions including support, food storage, moisture absorption, reproduction, floating, fungal symbiosis, and photosynthesis.

Supportive Roots

When plants are tall or heavy, adventitious roots modify to provide additional support. Various types of adventitious roots offer support to a plant including:

• Prop Roots: These roots grow downwards after emerging from the existing branches of the tree, and anchor into the ground upon reaching the soil.For example, banyan tree.
• Stilt Roots: Various small trees and shrubs grow in places where the anchorage is not strong like on the edges of tanks. In these cases, small roots grow diagonally downwards from the base of the stem, providing additional support like stilts. For example, Sugarcane plant
• Climbing Roots: Arising from the nodes, these roots attach themselves to a support and climb up using it, therefore providing support to the plant. For example, Money plant
• Clinging Roots: To hold the plant, these roots enter the gaps present on the support and anchor the plant. For example, orchids
• Buttress Roots: These develop at the base of a stem and are spread in different directions in the soil. These roots look like planks and prevent the tree from falling. For example, Bombax.
• Floating Roots: These roots found in certain aquatic plants like water hyacinth, water lettuce, etc., help the plant float. Additionally, it also helps the plant in nutrient absorption and respiration.
• Contractile Roots: These roots possess the ability to contract or shorten their length. This ability helps the plant to pull itself deeper into the soil, providing increased anchorage, and stability.
• Root Thorns: These roots, due to various environmental factors, evolve into sharp, pointed structures that serve various functions including protection and anchorage.

Also Read: Difference Between Prop Root and Stilt Root

Food Storage

Some adventitious roots undergo modifications to store nutrients efficiently. These include:

• Tuberous: These roots assume no shape but swell up upon storing food. Additionally, these roots arise from the nodes of the prostate stem. For example, sweet potato.
• Fasciculate: These roots, upon swelling up, assume a definite shape and grow in clusters at the stem base. For example, dahlia and asparagus.
• Nodules: In these roots, the apex of the roots swell up upon the storage of food, For example. mango, and ginger.
• Moniliform: The roots are beaded at fixed intervals upon the accumulation of food—For example, bitter gourd.
• Annulated: These roots give the appearance of numerous discs placed one on top of the other. For example, Ipecac.

Moisture Absorption

Adventitious roots known as epiphytic roots are aerial roots that hang from the plant’s body and have a porous wall that absorbs moisture from the atmosphere. As these plants have no contact with the soil, Velamen, a tissue present on these roots, absorbs and stores moisture. For example- Orchids.

Reproduction

In many plant species, adventitious buds grow on roots and plantings arise from the base. For example, sweet potato, and ipecac. Additionally, various plants with adventitious roots can reproduce vegetatively i.e. they can form from stems, leaves, or other non-root tissues, without the requirement for seeds.

Floating

The nodes of aquatic plants give rise to these roots which aid in both flotation and respiration. The plant remains buoyant in water due to the spongy nature of these roots, but when removed from their aquatic environment, these roots dry up. For example, Jussiaea.

Fungal Symbiosis

A type of adventitious root also known as mycorrhizal root is home to fungal hyphae. The fungus present absorbs water and minerals from the soil for the plant, and the plant, in return, provides the fungus with organic food. For example, Pinus

Also Read: Difference Between Ectomycorrhizae and Endomycorrhizae

Photosynthesis

Adventitious roots known as assimilatory roots are specialized roots that help in the uptake, conversion, and storage of nutrients and minerals in plants. Upon exposure to the sun, these roots develop chlorophyll and assimilate some carbon. Using these two components, these roots prepare food for the plants. These roots also play an important role in enhancing plant metabolism, and growth. For example, Tinospora

Haustoria Roots

These are specialized adventitious roots that penetrate the host plant tissue and absorb the water and nutrients. Haustoria roots help a parasitic plant survive and grow by facilitating its nutrient uptake from the host plant.

Modification of Roots is the process by which roots alter their shape to absorb and transport water and minerals from the soil to various parts of the plant. In addition, the function of roots includes absorbing water and minerals and transporting them to the stem, storing food, and providing support to the plant body. Root modifications emphasize a plant’s ability to survive. This article explains the modifications of roots, focusing on the modification of taproot and adventitious root systems.