The roots of plants which develop underground are known as underground roots. Various plants, such as some root vegetables and tap roots, which grow from the radicle and penetrate deep into the soil are known as underground roots. Root vegetables are grown underground; therefore; they absorb a large amount of nutrients from the soil. Some of the root vegetables are the most common examples such as carrot and radish.
1. Daucus carota
Daucus carota (Umbelliferae-Dicot) is the scientific name for carrot, a root vegetable. Carrots possess tap roots and these roots undergo several modifications for performing various functions like food storage. Carrot roots undergo modifications and form cone-like structures; therefore, are categorized under conical root modifications. These types of roots are thickest towards the base and gradually tapering towards the apex. The hypocotyl and the base of the stem after sloughing off the cortex become fleshy through the development of parenchyma in the phloem. Parenchyma is a simple permanent tissue that makes the storage tissue. The storage roots of this plant are usually swollen for the storage of various food materials.
Radish, also known as Raphanus sativus, is a Cruciferae- Dicot and an edible root vegetable belonging to the Brassicaceae family. Radish has a spindle-shaped structure, thickest from the middle and narrow from the ends, and is an example of fusiform tap root modification. The tapering/narrow ends include the base of the stem and the apex of the root. Xylem is the chief region for food storage but the storage also takes place outside the xylem region. Fleshy roots of radishes show a proliferation of parenchyma in the pith and the secondary xylem, accompanied by differentiation of concentric vascular bundles within this parenchyma. Radish is a rich source of antioxidants (calcium and potassium) and helps to lower high blood pressure levels and reduce the risk of heart diseases.
|Sub-species||R. raphanistrum sativus|
Its fusiform roots consist of swollen hypocotyl near the base and swollen taproot in the rest of the region. It is usually long and white color in appearance.
In European Radish, the taproot only forms the terminal tapering fleshy part of the root while the hypocotyl forms the middle fleshy parts. It is usually a short, red-colored taproot.
Brassica rapa, the scientific name of turnip, is an underground cruciferous vegetable that belongs to the Brassicaceae family. Turnips are also called top-shaped roots because of their structure and are categorized under napiform tap root modifications for food storage. The phloem and the cortex of turnip roots are narrow; therefore, food storage largely takes place in the xylem region. The massive swollen part of the turnip is the hypocotyl, while the taproots are present at the tapered/narrow end of the turnip. Various health benefits of turnip include-
- Help in lowering blood pressure
- Reduce the risk of cancer
- Help in weight loss
- Improves digestion
- Lowers the risk of intestinal problems
Beta Vulgaris or beetroot is a Chenopodiaceae-Dicot that belongs to the Amaranthaceae family. In beetroots, the alternate layers of the xylem and phloem leads to the formation of successive cambia. The secondary tissues of these roots accumulate starch in various parenchymatous and sclerenchymatous cells of the xylem and the phloem. Both the hypocotyl and roots of beet form swollen structure which helps to store food, starch, and water. Beetroot has a top-shaped structure and is an example of napiform taproot modification. Beetroots are rich in folate (vitamin B-9) which helps in cell growth and functioning. Folate helps to control the damage of blood vessels, thus reducing the risk of heart attack and stroke. Beetroot is also a rich source of diverse minerals such as potassium, sodium, phosphorous, calcium, magnesium, copper, iron, zinc, and manganese.
Horseradish is the common name for a perennial herb, Armoracia rusticana. It is grown as a spicy root vegetable and belongs to the Brassicaceae family. It is an easily cultivated edible root crop, which is mainly known for its pungent roots containing oil that has a strong pungent odor and hot biting taste. Large leaves and a flower stalk cover the top of the plant which rarely produces seeds. The roots of this plant are entirely underground; therefore, it is categorized as an underground root vegetable. Radish and horseradish are completely different plants as horseradish is spicier than radish and contains a strong flavor, whereas radish is slightly spicier with a milder flavor.
6. Celery root
Celery root (Celeriac) is a root vegetable that is well known for its strange appearance and is scientifically known as Apium graveolens. It usually looks like a misshapen turnip and has a rough, knobby surface covered in tiny roots. Its appearance is like a roundish bulb approximately, the size of a grapefruit. Similar to potato, it also has smooth white flesh. The roots of celeriac are underground which performs the storage functions for plant survival. Celeriac is a popular winter root vegetable and is commonly used in salads, soups, casseroles, and stews.
A parsnip is a long tapered root vegetable which belongs to the Apiaceae family. Although parsnips are a biennial root vegetable, they are generally grown as an annual. These plants usually contain cream-colored tuberous roots which are grown underground. They have one underground tap root and the greenery grows above ground. Seeds germination in this plant is slow and; therefore; it needs certain growing conditions to prevent deformities.
8. Mirabilis Jalapa
Mirabilis Jalapa is commonly known as a four O’ clock plant because the flowers of this plant open up in the late afternoon to produce a strong, sweet-smelling fragrance throughout the night and gets closed again in the morning. It is a perennial, herbaceous, bushy plant which belongs to the Nyctaginaceae family and is mainly found in temperate zones. Tap roots undergo modifications to form tuberous roots for storage purposes. Tuberous roots are the modified lateral roots for nourishment storage to store food and minerals. Tuberous roots produced in mirabilis jalapa are swollen, which stores nourishment and helps them to perennate through dry and cold periods.
9. Trichosanthes (Vern. Parwal)
Trichosanthes dioca, also known as pointed gourd, is a tropical perennial cucurbit plant which belongs to the Cucurbitaceae family. In regions of India and Bangladesh, it is also known as parwal or palwal. Trichosanthes plant has tuberous roots which are the modifications of tap roots for storage purposes. Despite growing underground, largely in darkness, roots emerge to be very sensitive to light. This plant is cultivated mainly as a vegetable, and also the leaves of this plant are used for its antipyretic, diuretic, cardiotonic, laxative, and antiulcer effects.
10. Ruellia tuberosa
Ruellia tuberosa, commonly known as cracker plant/minnieroot, is a small biennial plant from the Acanthaceae family containing thick fusiform tuberous roots (storage roots). Fusiform tuberous roots are modified forms of tap roots developed for storage purposes. The storage roots of this plant get swollen and fleshy to store food and minerals and the fruits of this plant are 2-3 cm long spindle-shaped capsules. Ruellia tuberosa is traditionally used as a diuretic, antipyretic, analgesic, anti-hypertensive, anthelmintic, abortifacient, and as an emetic in various disorders like bladder disease, kidney disorder, bronchitis, gonorrhea, and syphilis.