What goes on in the roots? (A quick introduction!)

Roots are necessary to anchor the plant to the soil. They are essential to the survival of the plant as they absorb and store the essential nutrients for its development. Not all plants have roots. Moss, for example, absorbs water and nutrients directly from the atmosphere. Plants that do have roots are known as vascular plants.

Two main types of roots are taproot and fibrous root. These can be illustrated by looking at some common vegetables.

A taproot is a thick, central root which digs deep down into the ground to find minerals. If you think about carrots (Daucus carota) and parsnips (Pastinaca sativa), you get the idea. These vegetables, known as root crops, are swollen taproots. They are full of nutrients which provide a valuable source of food for us. Carrots contain many important nutrients[1] including carotene which is converted into vitamin A (retinol) by the human digestive system. Vitamin A is important for vision[1], which is why my grandmother used to say "If you eat all your carrots, you'll be able to see in the dark". Calcium, potassium, magnesium, zinc and iron are all present in parsnips along with protein, fibre and vitamins B5, B6, C, E and K[2].

In contrast, vegetables such as garlic (Allium sativum) and onions (Allium cepa) have fibrous roots. This type of root system plays an important role in preventing soil erosion as the roots bind the soil together. The thin roots develop fairly shallow. They depend on the surface area of the soil for their nutrition and are very effective in absorbing and transporting minerals. Allicin is an organosulphur compound found in both garlic and onions. This molecule is responsible for the pungent smell when you crush a bulb of garlic and it has a potent antimicrobial action[3].

Roots do not always work alone. A large number of plants work in symbosis with soil fungi to maximise plant development and growth. In exchange for food the plant generates by photosynthesis, the mycorrhizal fungi facilitate the access and absorption of nutrients and water by the roots.

Often roots are found in the ground but sometimes they are visible as in the case of adventitious roots. This type of root can grow from various parts of a plant such as stems, bulbs or rhizomes and allows the plant to spread across a large surface. One example of this is common Ivy (Hedera Helix) which attaches itself securely to a support and climbs up using aerial roots produced from its stems.

Whether we can see them or not, it is clear that roots play a vital role in the survival of vascular plants.

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[1] Varshney, Khyati & Mishra, Kirti. (2022). An Analysis of Health Benefits of Carrot. International Journal of Innovative Research in Engineering & Management. 211-214.10.55524/ijirem.2022.9.1.40.

[2] https://fdc.nal.usda.gov/fdc-app.html#/food-details/170417/nutrients

[3] Pengelly, A (2021) The Constituents of Medicinal Plants CAB International.