Roots

The most important function of roots is to take in the water, minerals, and nutrients that the plant needs to grow. They also anchor plants and store food for future use.

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Anchoring the Plant

Table of contents heading: Anchoring the Plant

Forest fig (Ficus craterostoma, left and center) and wild fig trees (Ficus insipida, right) have thick roots that anchor them in the soil. Photos by Ibarionex Perello and Jamie Pham. | The Huntington Library, Art Museum, and Botanical Gardens.

Roots help anchor plants in place, so they don’t get knocked over or washed away by wind, rain, animals, swampy soil, or other environmental forces. Most of the time, roots form underground, but some plants grow roots above ground from their trunks or stems. These aerial or prop roots grow downward into the soil and help keep the plant upright. Eventually, as they grow close to the tree, they can become part of its trunk.

Forest fig trees (Ficus craterostoma) grow thick aerial roots (left) that help support the tree and eventually become part of the tree’s trunk (right). Photos by Ibarionex Perello. | The Huntington Library, Art Museum, and Botanical Gardens.

Banyan trees (Ficus benghalensis), a type of Ficus, and mangrove trees are famous for their prop roots, which help them stay upright. Some vegetables, like corn, also grow these supportive roots.

Taking In and Storing Water and Nutrients

As they swell, roots can be strong enough to break rocks, but their delicate tips absorb water, minerals, and nutrients in the soil to help plants live and grow. While all plants need these essential resources, depending on their environment, plants have different systems for accessing and absorbing them. In dry habitats, plants need roots that help them tap nutrients in the surrounding soil, and sometimes roots can swell with stored water and nutrients. A taproot is a single main root (often with smaller, outward roots) that grows into the soil to access underground moisture. Other plants have fibrous roots that branch out just beneath the soil surface, forming a dense network that can absorb dewdrops or condensation from fog. Some plants produce tubers to store food and water since they don’t have refrigerators or cupboards. For example, potatoes and sweet potatoes use their roots for storage. When we eat these vegetables, we eat the nutrients and water the plants stored in their roots.

Table of contents heading: Taking In and Storing Water and Nutrients

Carrots (Daucus carota), onions (Allium cepa) and sweet potatoes (Ipomoea batatas) display three different kinds of roots, respectively: taproots, fibrous roots, and tubers. Photos by Max Tepper and Adobe Stock. | The Huntington Library, Art Museum, and Botanical Gardens, and Adobe Stock.

Root Life Cycle

To explore how roots grow, zoom in on the different parts of this image to explore the life cycle of a radish, which stores food and water in its roots.

Table of contents heading: Root Life Cycle

“The Life of a Radish” by Lisa Pompelli (1994) depicts the life cycle of radishes, from germination to going to seed. | The Huntington Library, Art Museum, and Botanical Gardens.

Germination: Inside a radish seed is a tiny root called a radicle. In germination, the primary root emerges.
Growing downward: The taproot grows downward and other roots branch off. Their tips absorb nutrients.
Photosynthesis: The leaves above ground start to photosynthesize. The plant now has access to the food it makes from sunlight.
Storage in the root: The plant uses some of the food to help it grow bigger and stores the rest in the root.
Root growth: The root gets fatter and juicier as more water, food, and nutrients are stored inside it.
Ready to harvest: If the radish is meant to be eaten, it’s harvested at this stage, when the root has stored as much food, water, and nutrients as possible.
Ready to bloom: Growing flowers and fruit takes a lot of energy. The radish transports food, water, and nutrients up the stem to help the plant grow the flowers it needs for reproduction.
Going to seed: Now that the radish has flowered, its root toughens. Though it still draws water and nutrients and continues to anchor the plant, it no longer stores extra resources.