Adventitious Root System: Types, Modifications and Examples

Adventitious root system

Root system mainly consists of two types, tap roots and adventitious roots. Adventitious roots are the type of roots that arise from parts of the plant other than the radicle. These roots can arise from the injured root, nodes of the stem, internodes, branches, or any other tissue. A mass of adventitious roots along with its branches constitutes an ‘adventitious root system.’ The adventitious root system is different from the taproot system in such a way that instead of having one primary root from which the branches arise, there are numerous morphologically similar roots arising from the same node in adventitious roots.

Difference between taproot and adventitious roots

Adventitious roots are generally seen growing from aerial parts of the plant. Adventitious roots can grow from the leaf and stem cuttings when placed in the soil. They are formed from the shoot cells and are found in both monoct and dicot plants. Their formation may be a result of unsuitable conditions like low oxygen environments, or high ethylene conditions. Other reasons for the formation of adventitious roots is when the stem cells divide into root tissue. In this lesson, we will learn about the types (modifications) of the adventitious root system with suitable examples.

Modifications of Adventitious Root System

Adventitious roots are modified for mechanical support, climbing, clinging, and to perform other vital functionswhich are necessary for plant survival. Unfavourable conditions for plant leads to the  The adventitious roots are modified so as to:

  1. Store Food
  2. Provide Support
  3. Carry Out Additional Functions

Modifications of Adventitious roots

1. Storage of Food

A. Tuberous Roots

Modifications of Adventitious roots- Tuberous Roots

Tuberous roots are the modification of adventitious roots. They are fleshy, do not have any particular shape, and often get swollen. In the case of tuberous roots, shoots sprout from one end while roots arise from the other end.

Example- Sweet Potato (Ipomoea batatas)

B. Fasciculated Roots

Modifications of Adventitious roots- Fasciculated roots


Fasciculated roots occur in the form of clusters. These clusters arise from the base of the stem.

Example- Dahlia

C. Moniliform Roots

Modifications of Adventitious roots- Moniliform Roots

Another modification of the adventitious roots is the moniliform roots. These roots are also swollen. However, the swelling in moniliform roots occurs at regular intervals which renders a beaded appearance to the roots.

Example- Rose moss (Portulaca grandiflora)

D. Annulated Roots

Modifications of Adventitious roots- Annulated Roots

In this type of modified adventitious roots, a series of outgrowths, which resemble the shape of rings, are present on the body. The series of these outgrowths looks like discs stacked one above the other.

Example- Ipecac (Cephaelis ipecacuanha)

E. Nodulose Roots

Modifications of Adventitious roots- Nodulose Roots

Nodulose roots are the modification of adventitious roots which are swollen at the apex or tips. They possess a characteristic shape.

Example- Turmeric (Curcuma longa)

2. Mechanical Strength

A. Prop or Pillar Adventitious Roots

Prop Roots

  • These are the type of adventitious roots which grow in downward direction from the branches of the trees. These roots are modified to support the thick and heavy branches.
  • The aerial roots are hygroscopic, that is, they absorb water (present in the form of moisture) from the air. Due to moisture absorption, these roots turn red in colour.
  • Prop roots have root caps on their tips. As the prop roots reach the soil, they become thick and pillar-like. At this point, it becomes difficult to distinguish between the trunk and prop roots.
  • An interesting fact is that even if the trunk dies, the tree as a whole remains alive because the prop roots of the tree are supporting and nourishing the crown.

Examples of prop roots:

The Great Banyan growing in Acharya Jagadish Chandra Bose Indian Botanic Gardens, Howrah is nearly 250 years old and has 1775 prop roots. The main trunk of this Banyan tree decayed years ago. The circumference of the crown of this tree is around 404 m.

The largest tree specimen in the Guinness Book of World Records is found in Thimmamma Marrimanu village of Anantapur district in Andhra Pradesh, India. It is spread over an area of 5.2 acres.

The Great Banyan Tree

  • Mangrove plant (Rhizophora) )

Rhizophora Roots

B. Stilt Roots

Stilt roots

Stilt roots

These roots arise obliquely from the basal node of the stem and then penetrate the soil. These roots are short but thick and are modified to support the plant. After penetrating the soil, they get modified into fibrous roots and help in water and mineral absorption.


  • Sugarcane (Saccharum officinarum)
  • Maize (Zea mays)
  • Fountaingrass (Pennisetum setaceum)
  • Sorghum (Sorghum bicolor)
  • Screwpine (Pandanus odoratissimus0

C. Climbing Roots

Climbing Roots

Climbing Roots

  • These roots are found in climbers (plants climbing on various structures). They are non-absorptive kinds of adventitious roots that help the plant to remain adhered to the structure.
  • Climbing roots penetrate the cracks or fissures of the support and help the plant climb. These roots form claws, swell, or secrete sticky juice from their tip to hold the support firmly.
  • A tendril-like root arises from the node in the case of the Vanilla (Vanilla planifolia) plant. Therefore, they are known as tendrillar roots.
  • The climbing adventitious roots may also sprout from each node and get branched. Such types of climbing adventitious roots are known as clinging roots.


  • Tecoma (Tecoma stans) and Betel (Piper betle): roots arise from the nodes.
  • Climbing Fig (Ficus pumila): roots arise from the internodes.
  • Ivy (Hedera): roots arise from the nodes and internodes. The tip of the roots secrete sticky juice to hold the structure firmly
  • Tecoma (Tecoma stans): roots form claws for climbing.

D. Buttress Roots

Modifications of Adventitious roots- Buttress Roots

  • Buttress roots develop at the base of the stem and help in maintaining the structural integrity of the plant.
  • The basal part of the stem, which is vertically elongated, spreads in different directions in the soil.
  • This type of modified adventitious root gives the appearance of planks.


  • Arjuna Tree (Terminalia arjuna)
  • Cotton Tree (Bombax ceiba)
  • Moreton Bay Fig Tree in Santa Barbara, California (Ficus macrophylla)

3. Additional Functions

A. Assimilatory Roots

examples of Assimilatory roots

Assimilatory roots

  • These roots are modified for carrying out vital functions of the plants.
  • These are green roots that are capable of performing photosynthesis due to the presence of chloroplast in their cells.
  • Assimilatory roots are highly branched to increase their surface area so that the maximum amount of sunlight is absorbed by them.


  • Water Chestnut (Trapa natans): their roots are submerged like normal roots
  • Moonseed (Tinospora cordifolia): its assimilatory roots, arising from stem nodes, sprout during the rainy season and wrinkle during drought
  • Ribbon Roots (Taeniophyllum)

B. Epiphytic or Aerial Roots 

Aerial roots of orchids

Epiphytic Roots

  • Aerial roots are the type of adventitious roots that are present in epiphytes, that is, on those plants that live on other plants for shelter and nutrition.
  • Epiphytic roots are irregular in shape and hang down the surface of the other plants. These roots do not possess a root cap and, instead, have a covering of a dead spongy tissue known as velamen.
  • Epiphytic roots are hygroscopic in nature, that is, they absorb water, present in the form of moisture, from the air with the help of velamen.

Epiphytic plants possess two types of roots; for clinging (or fixation) and for the absorption of mineral salts and moisture from dust collected on the bark.


  • Orchid (Orchidaceae)
  • Vanda
  • Dendrobium (Dendrobium aggregatum)

C. Floating Roots

Floating roots

Floating roots

  • This type of adventitious root modification is found in aquatic plants.
  • These roots arise from the node of the horizontal floating stem.
  • Some of these adventitious roots store water and become inflated. The inflated roots come out of the water surface and help the plant to float.
  • They also help in gaseous exchange, therefore, they are also called respiratory roots.


  • Ludwigia

D. Mycorrhizal Roots

Modifications of Adventitious roots- Mycorrhizal Roots

  • Mycorrhizae refer to the symbiotic association of a fungus with a higher plant.
  • The mycorrhizal roots present a classic example of a mutual association between a fungus and roots.
  • The nutrients from the soil are absorbed by the fungus. The plant, in turn, supports the fungus with organic food.


  • Pine (Pinus sabiniana)
  • Monotropa
  • Snow Plant(Sarcodes)

E. Sucking Roots or Haustoria

Modifications of Adventitious roots- Sucking Roots or Haustoria

  • In order to absorb nutrients from the host, parasites develop microscopic roots which are known as sucking roots.
  • Since they are also found in non-green parasitic plants, they are also known as Haustoria.
  • Sucking roots sprout from the nodes and penetrate deep into the conducting tissue of the host to obtain nutrients.


  • Dodder (Cuscuta)
  • Mistletoe (Viscum album)

F. Reproductive Roots

Modifications of Adventitious roots- Reproductive Roots

  • Reproductive roots are modified adventitious roots which help in reproduction.
  • Such kind of adventitious roots gives rise to buds which further develop into shoots.
  • A root cutting can be planted in the soil from which a new plant grows.
  • The reproductive roots form one of the ways of vegetative propagation.


  • Sweet Potato (Ipomoea batatas)
  • Dahlia

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