Root System
7 Minutes
Plant root systems for kids: learn how roots grow underground, absorb water, and differ between tap and fibrous roots. A science lesson in English.
- Root caps, root hairs, and how roots grow down into the soil
- Tap root systems with primary, secondary, and tertiary roots
- Fibrous root systems in grass and food storage in carrots
What this lesson teaches
A root system is the part of a plant that grows below the ground to anchor the plant and take in moisture and nutrients from the soil. While the shoot system grows above the ground, the root grows downward toward the earth, making it positively geotropic.
Parts of a root
When a seed begins to grow, the root pushes down into the soil to seek out water, minerals, and physical support. The delicate growing tip of the root is covered and protected by a root cap, which prevents damage just like a pen cap shields a pen tip. Along the root cap, tiny hair-like growths called root hairs emerge into the soil. These fine root hairs carry out the vital job of absorbing water and dissolved minerals for the plant.
The tap root system
A tap root [ani ver] features one thick main root called the primary root that drives straight down into the earth like a nail. From this central primary root, larger side branches called secondary roots grow outwards. These secondary roots branch further into tertiary roots, which end in tiny rootlets. This deep and sturdy network is common in large plants that require strong anchorage, such as mango trees.
The fibrous root system
A fibrous root system is made up of numerous thin, thread-like roots that grow in a cluster from the base of the plant. Unlike a tap root, these roots are mostly uniform in thickness and spread through the soil like a bundle of fine noodles or fibers. Grass is a typical example of a plant that anchors itself using a fibrous root system.
Root functions and food storage
The primary role of any root system is to grip the ground firmly and draw up the water and minerals the plant requires to live. In certain plants, roots also perform a special function by changing their form to store food substances. Carrots and beetroots are examples of plants whose roots swell underground with stored food.