Tap Root Diagram

Taproot Diagram illustrates that a taproot is the thick primary root of a plant that develops vertically downward into the soil and branches out into smaller lateral roots. Plants usually have one of two root systems: a taproot system or a fibrous root system. In contrast to fibrous roots, which are thin and branched, taproots have a conspicuous central axis. In this article, we will study the characteristics and functions of the taproot with a well-labeled diagram showing its different parts and structure.

What are Tap Roots?

Roots are the underground portions of a plant that gives stability and absorb nutrients. Plants have three primary kinds of root systems: Fibrous Root System, Adventitious Root System, and Tap Root System. Taproots mostly found in dicotyledons, are made up of a central, big root that is called the taproot. The diameter of the taproot is greater than that of the lateral roots.

Lateral roots originate from the pericycle and branch off from the taproot, and other subsequent lateral roots can branch off other lateral roots. Taproots generally grow deeper into the soil than do fibrous roots. Dicot plants with taproots include parsnips, dandelions, carrots, radishes, beetroots, and grams. As seen in carrots, beets, and other plants, they can also be modified for support or food storage.

Diagram of Tap Root

Below is a well-labelled Taproot Diagram.

Structure of Tap Root

Structure of the taproot is as follows:

• The taproot system is made up of primary root or tap root, secondary root, tertiary root, root hairs, and root cap.
• A taproot system consists of single, thick, cylindrical primary root that emerges from the radicle of the cotyledon. It develops into an extremely thick, straight, and slender mass.
• Smaller roots that branch out from the primary root (lateral branches of the primary root) are known as secondary and tertiary roots. They provide support to the plant.
• A thin, hair-like structure called a rootlet is located at the tip of the tertiary root and is essential for the plant’s ability to absorb water from the soil. A root cap that covers the tip of the root continues to shield the young, fragile root as it penetrates into the ground.
• This kind of root system is usually deeply rooted, difficult to remove, and it keeps the soil from eroding while also giving the plant stability.
• Under drought conditions, plants with a taproot system will have better sustenance because their roots may penetrate deeply into the soil.
• The root formation takes place in acropetal succession, meaning youngest or the newer part is found near the growing end of the taproot and the oldest towards the base of the stem.
• The taproot has a vertical orientation, secondary roots are oblique or horizontal, and tertiary roots run in various directions. The ultimate root branches are called rootlets. Root hairs originate from the epidermis of the primary root.

Regions of Root

Four distinct regions/ zones are present in any true root:

• The root cap
• Areas of meristematic activity (cell division)
• Elongation (which causes the root to lengthen as it grows)
• Maturation (where root hairs emerge). Since the cells differentiate into several primary tissue types, the maturation region is also referred to as the region of differentiation.

Characteristics of Taproots

Taproots have a number of unique characteristics such as:

• Emergence from the radicle of the seed, establishing it as the primary root.
• A prominent central axis that extends directly downward.
• Secondary and tertiary lateral roots branch out from it, producing a complex network-like root system.
• They can because they are often thicker and longer than fibrous roots.
• Taproots are usually straight, thick, and taper towards the end.
• For optimal growth, taproots penetrate deeper into the mineral-enriched soil.

Functions of Tap Root

Functions of the tap root are as follows:

• Anchorage: The primary function of the taproot is to provide deep anchorage, holding the plant firmly to its ground and thus preventing it from toppling over by heavy rains or strong winds.
• Storage: Taproots of carrot, sugar beet, radish, beetroot, parsnip, and others are modified into storage organs. The stored food reserves are consumed during adverse conditions or for the plant’s growth and development.
• Absorption: Taproot also contributes in the absorption of nutrients and water from the soil. It helps to access water from deeper layers of soil, helping the plant to survive in arid climates or during periods of drought. In addition, it also helps plants to absorb vital nutrients, such as nitrogen, phosphorus, and potassium, from deep within the soil required for plant growth and metabolism.
• Respiration: Plants growing in swamps develop pneumatophores which are also known as respiratory roots. The surface of the root has microscopic pore-like structures called pneumathodes that assist in gaseous exchange. For example: Red mangrove.
• Nitrogen fixation: Several taproots have irregularly inflated nodules. With the aid of Rhizobium, which are bacteria that fix nitrogen, they are able to absorb free nitrogen from the atmosphere and transform it into organic molecules. For example: Soybean.

Types of Tap Root

Tap roots come in a variety of forms. Tap roots often have the following shapes:

• Conical: The primary or the main root is wide at the base of the stem and becomes narrower towards the root’s tip. This kind of root resembles a cone because it has one enlarged end and one tapering end. There are numerous secondary and tertiary roots that resemble threads along its entire length. Example: Parsnip.
• Napiform: This fleshy root has a spherical appearance and is thick at the stem’s base. The taproot swells from the stem’s base and tapers abruptly. Example: Beetroot.
• Fusiform: This version of taproot is tapering at both ends and is broader in the middle. It is thickest in the centre and narrowest at the ends, resembling a spindle. Sweet potatoes is one example.
• Storage: A tuberous root is a fleshy root that has been enlarged and adapted to store food. These are known as the storage taproots and they do not have any particular shape or form.

Examples of Tap Root

Taproots are mostly found in dicotyledonous angiosperms and gymnosperms. In plants such as beetroot, it functions as the main storage organ and is a famous vegetable around the world. The Indian spice Asafoetida is derived from the latex of the taproots of Ferula species.

Few common examples are: Sweet potato, Beetroot, Carrot, Parsnip, Radish.

• Taproot trees: Walnut tree, Peach tree, Spruce, Ash tree, Douglas fir.
• Taproot weeds: Canada thistle, Common dandelion.
• Taproot vegetables: parsnip, sweet potato, burdock.

Adaptations of Taproots

Taproot plants have developed unique adaptations to fit their surroundings:

• To thrive in arid environments, desert plants, such as cactus and acacia, have developed taproots that allow them to get water deep underground.
• Some biennial plants, such as beets and carrots, store food reserves in their taproots during the first year of their growth and these reserves are used to generate seeds and flowers during the second year.
• Plants with large and extensive taproot systems, such as trees, can help avoid soil erosion by deeply anchoring themselves into the ground.

FAQs -Tap Root Diagram

What are Adventitious Roots?

Adventitious roots are formed from plant parts other than the primary root system.

What are Stilt Roots?

Stilt roots are a type of adventitious roots that emerge from the lower nodes of a stem and grow vertically down into the soil.

What are the Tap Roots of a Plant?

A huge independent root that extends downward from the base of the plant is referred to as a taproot. Smaller, hair-like roots that branch off of the major root are common in taproots.

What are the 4 Parts of the Tap Root System?

The four main parts of Tap root system are: Primary root, Lateral roots, Root hairs and Root cap.

What are Root Pockets?

The non-functional or vestigial root caps are called root pockets. This is because plants with roots that dangle freely in water typically encounter little resistance or friction from the soil particles.