Function of roots in plants

There are the main functions of roots in plants as well as some secondary root functions; all these are very important and essential because the roots help the plant carry out essential life processes such as growth, development, and reproduction.

Table of Contents

What is the function of roots in plants?

Roots function in plants is divided into primary and secondary functions. With the primary being, the main functions, and the secondary classified as the other functions of roots in plants.

Primary function of roots in plants

  1. The main function of roots in plants is for anchorage
  2. One function of roots in plants is that it aids in the absorption of water
  3. Another major function of roots in a plant is for the absorption of minerals
  4. Roots functions in the aspect of transportation of absorbed substances
  5. Lastly, the primary function of roots for a plant is for the prevention of soil erosion


Anchorage comes from the word anchor like a ship anchor that helps the ship to stay put without drifting into the open waters and this function helps plants to stay upright and firm in the soil. The roots of plants play this particular role in supporting the stem and the leaves, and in making sure that the whole plant is not uprooted easily.

Absorption of water

Plants need to replenish lost water from transpiration is done by root hairs through the absorption of water from the soil. Root hairs are little tiny extensions of the root that aid in absorption. This uptake of water through the roots by virtue of the roots hairs is achieved because of some certain characteristics that the root hairs possess. Such characteristics include the ability to increase the root surface area in order to increase the rate of water absorption, the presence of a higher concentration of cell sap in the root hairs than the surrounding environment in order to absorb water through osmosis, and the possession of thin permeable cell wall that allows for the free movement of water in and out of the cell.

Absorption of minerals or nutrients

Just like the function of roots in absorbing water, plants use the same method to absorb minerals or nutrients that they need for their growth and development. Root hairs are the chief architects in this process as they help to take in sparingly soluble minerals and send them to the parts of the plants where they are needed.

Transport of absorbed substances

The roots of a plant help in the transportation of the already absorbed water and nutrients to where they are used in the plant. The xylem helps in this one-way flow of water and nutrient to the leaves and shoots of the plant. Transport is essential to the growth and development of a plant, and it is one of the main functions of the roots to aid in this process in plants.

Prevention of soil erosion

Plants frequently bind the soil together with their root systems, allowing them to act as a protective layer that can help prevent soil erosion in a variety of ways. Firm plant placement in the ground, for example, slows water flow because the stems act as thick barriers. The roots of the plants also hold the soil in place, making it more difficult to wash away accidentally. Plants also help break down the impact of raindrops before they hit the ground, protecting the soil from direct rainfall, and this aids in the prevention of soil runoff.

Secondary function of plant roots

  1. Storage
  2. Extra or mechanical support
  3. Climbing
  4. Perennation
  5. Nitrogen fixation
  6. Aeration
  7. Reproduction
  8. Floating
  9. Balancing
  10. Photosynthesis
  11. Attachment
  12. Mycorrhiza
  13. Growth regulators

These secondary functions are the other function of roots in a plant

radish plant roots is an example of a secondary function of roots in plants
Radish plant roots are examples of the function of roots in storage.


Storage roots in plants like Momordica, Curcuma, Ipecac, radish, sweet potato, carrot, turnip, and mirabilis have been specially modified to store starch and water. They typically grow underground to protect themselves from plant-eating animals. These storage roots are mostly fleshy roots that function in the storage of energy for the plant during scarcity.

Extra/mechanical support

The extra or mechanical support root provides to plants includes attachment and fixation to the soil. In this case, roots establish a close network that creates a close association with these soil particles to stand really firm in the soil. For example, prop roots act as a pillar for heavy branches, particularly those that are more horizontal in nature, such as banyan trees. Another example is that of plants with a weak stem that bends toward the soil and is thus supported by stilt roots from one side of the leaning stem, such as seen in the screw pine plant.

What is the physiological function of roots?

The most important physiological functions of the root are the active and passive absorption of water and mineral nutrients. Another physiological function is the conduction of water and nutrients that are transported to different parts of the plant body via the root’s xylem elements.
In addition to the physiological function of roots in a plant is the aspect of storing food, especially when it comes to fleshy roots plants like sweet potato, turnip, radish, and beet.


Climbing roots function by assisting some of the weak-stemmed plants. This is achieved by penetrating the cracks of the support, as in Pothos (money plant), or by secreting a cementing gummy substance, as in Ficus pumila.


The function of perennation by the roots of a plant is usually found in plants with a tap root system. These roots are able to store enough sugar that will be sufficient for the plant throughout the winter season and before the next germinating season. The term perennation is the ability of a plant to survive from one germinating cycle to the next germination cycle under unfavorable conditions (winter).

Nitrogen fixation

This type of root function is carried out by the root nodules of some specific plants especially legumes. The nodules in the roots are formed by bacteria (rhizobia) and these microorganisms help the plant to fix nitrogen gas in the atmosphere into ammonia. This ammonia is used by plants in the formation of amino acids and nucleotides. This function is only found in conditions with limited nitrogen supply.


This role and function help the plant to have more access to oxygen in the soil through the ability of some roots like tap roots to penetrate the soil and break down compacted soil. This needed oxygen helps the plant to perform photosynthesis in order to grow properly. Because the lack of available oxygen for the plant to use will hamper the growth of the plant.


To reproduce or propagate means to multiply oneself and propagative root structures are one method for a plant to multiply. This process occurs when plants produce adventitious buds (buds that appear in unexpected places) that will now develop aerial stems and rootlets leading to the production of a new plant that is detached from the original and grows on its own. Some plants will send out propagative roots of up to 30 feet or more from the parent plant.

On a whole, this function of roots in these types of plants (strawberries, horseradish, and cherry tree) aid in the continuation of their lineage from generation to generation.


Floating roots are variants of adventitious roots and these roots grow from the node of plants that live in the aquatic system. They are spongy roots filled with air, and they function by helping the plant float through the provision of buoyancy to the plant. These roots inflate the plant, allowing it to float on the surface of the water and creep across the surface of wetlands.


This function contributes to plant balance because roots are typically positively geotropic, meaning, they grow down into the soil; and are positively hydrotropic, which means that the roots grow towards the source of water, and they are negatively phototropic i.e. they grow away from sunlight. While the plant’s upper side, the shoot or stem, is negatively geotropic (i.e. grows upward from the soil) and positively phototrophic (i.e. grows toward sunlight). In other words, creating a balance in the whole body of the plant.

Also, this other function of roots can be observed in aquatic plants that use their roots to maintain balance and float on the water surface without submerging.


This is another secondary root role and function in plants because water, carbon dioxide, chlorophyll, and sunlight that are required for photosynthesis are provided by the roots. Also, trace elements like magnesium are also required during photosynthesis and these elements and many more are obtained by the roots from the soil.


Plants with secondary functions, such as English ivy, can attach themselves to nearly any surface using a strategy involving natural-forming glue and shape-changing root hairs. The ivy sprouts thin roots along the underside of its stems, which can cling to small surface bumps on trees, rocks, and building plaster. Once the roots have settled in, they secrete a glue-like substance to help them stay in place. The root can change shape and scrunch itself into a tight spiral shape around its attachment point as a final means of securing a tight hold.


Roots provide necessary nutrients for the growth of the mycorrhiza which is a fungus. In exchange, the large mass of fungal hyphae works as a simulated root system for the plants, increasing the quantity of water and nutrients available from the surrounding soil.

Growth regulators

Roots aid in the production of cytokines, which are growth regulators produced in areas where cell division occurs. This growth regulator promotes the growth of new leaves, lateral shoot growth, chloroplasts in leaves, and other processes. Cytokines aid in the overthrow of apical dominance and the postponement of leaf aging.

Primary vs secondary function of roots

Primary root function
Secondary root function
Absorption of water
Extra or mechanical support
Mineral Absorption
Transportation of absorbed substances
Nitrogen fixation
Prevention of erosion
Reproduction or propagation
Growth regulators
A table showing the difference between the primary and secondary function of roots in plants

FAQ on the function of roots in plants

What is the main function of roots?

The main function of roots in a plant is to anchor the plant, absorb water and nutrient from the soil, prevent soil erosion, and transport the absorbed substances to the stem and leaves.

How do root hairs aid in the function of roots?

Root hairs aid in the absorption of water and minerals by increasing the root surface area in order to increase the rate of water absorption, another way is by providing a higher concentration of cell sap in the root hairs than the surrounding environment in order to absorb water through osmosis, and the possession of thin permeable cell wall that allows for the free movement of water in and out of the cell.

What is the function of roots in flowers?

Flowering plants would be unable to extract water or nutrients from the soil, or even stand upright, if they lacked roots. Some flowers have even evolved special roots that allow them to survive in harsh environments.

Is gas exchange a function of roots?

Yes, gas exchange is a function of roots especially when it comes to the absorption and release of CO2 and O2. But the gas exchange happens at a much lower rate.

What is the function of roots in a seedling?

The roots of a seedling help in the absorption of water and mineral necessary for growth.

How do the structure and function of roots help plants carry out life processes?

The structure and function of roots help plants carry out life processes through the absorption of water and minerals for growth and by acting as a balancing organ for sunlight to touch the leaves and stems. Another function is the ability of roots to absorb minerals, gasses, and water that are essential for photosynthesis to occur and some roots have propagative abilities to reproduce and continue the next generation.

A video briefly explaining the function of roots in plants