Difference Between Taproot and Fibrous Root

The roots of a plant are the extensions under the soil that supplies the plant with all the nutrients it requires to germinate. The first component that sprouts from the seed is a radicle from the bottom of it, and the plumule soon starts germinating towards the soil. The primary root and the baby plant support and protect the seed. The radicle grows into a taproot in some plants, such as beetroot and carrots.

This taproot growth occurs in gymnosperms (plants in which the ovule is bared for reproduction) and dicots (flowering plants with two cotyledons). The growth happens digressively, and the subsidiary roots grow sideways from the radicle to shape into a taproot which also serves as food storage for plants such as carrots. It is plump and linear, germinating typically towards the stimuli, i.e., groundwater. The storage competence is so advanced that the roots are nutritious.

Monocots (flowering plants that contain one cotyledon, such as grass, tulip, and garlic) produce a bunch of root dispersions that jut out from the surface of the stem, and they all have equal diameters. The roots are thin and well-balanced. The lump of roots grows deeper into the ground as the plant germinates into a tree.

This phenomenon occurs in many plants where first, the taproot grows. After a few years, the network of fibrous roots replaces it, where the roots grow perpendicularly and laterally. For the common tree of length 30-50 m, more than 95% of its root system expands perpendicularly and will be only 50cm under the soil. Plants with fibrous root systems are rice, maize, banana, etc.

Taproot

The taproot germinates into an embryonic radicle among the three types of roots. The lateral expansions arise from one taproot after another (secondary and tertiary roots), but the network remains short and unbundled. The area for food, nutrients, and water increases due to the thickness of the roots.

Framework of Taproot

1. The primary, secondary, and tertiary roots form a connected network. However, they can still be distinguished from one another till they get transformed into fibrous root systems.
2. The vertical roots are formed through the continual growth of rootlets linked to the root branches till the apexes of dorsal and ventral roots. These are the smallest root hairs capable of storing water and nutrients by increasing their surface areas.
3. The tap root system is profoundly located and is stronger than the other root types.
4. The older roots' growth begins from the surface of the stem under the soil, and the younger roots grow the apex of root extensions and establish themselves deeper into the ground. This process is known as acropetal succession.
5. The tap roots are composed of four important regions:
   
   
   1. Root Cap: The word cap means "take," which signifies the storage quality of root caps. It is a structure of parenchyma cells that are spindle figured and has multiple layers. The root caps are present at the root tip of the plant. Its function is to protect the root tip from environmental damage and help the root to propagate towards gravity due to the presence of Statocytes. It is due to the presence of the root cap the roots grow in an organized manner. The root cap is also known as Calyptra. It needs to be continuously replaced because it gets damaged easily. Through and through, the root size of the root cap remains constant while the roots grow. Some instances of root caps are liverworts, mosses, and hornworts. The root caps require water to grow from dew or rain.
   2. Region of Cell Division: This region lies near the root tip, and the meristematic cells constantly get divided here as the plant germinates.
   3. Region of Elongation: The newly formed cells grow in size, increasing the roots' size.
   4. Region of Cell Maturation: In this zone, the differentiation of cells into specialized cell types starts from the first root hair.

Functions of Taproot

• Tap roots fulfill the necessities of a plant for further growth.
• The tap roots burrow deep into the soil to stabilize and support the plant.
• For photosynthesis, tap roots provide important minerals such as nitrogen, potassium, phosphorus, and water to the plant.
• Through the osmosis process, the tap roots control the water or turgor pressure to maintain the balance of the plant by creating pressure inside the cells.
• The taproots settle inside the soil so deep that they can survive using groundwater, even in dry lands. During drought or the absence of sunlight for a long period, the tap roots help the plants by using the nutrients they collect.
• Through photosynthesis, the taproots serve as a storage space for food materials, and the roots grow into edible vegetables as nutrients and carbohydrates are available to them.
• The gaseous exchange in the roots of plants that grow in marshes occurs through microscopic apertures known as pneumatophores. These respiratory roots are called pneumatophore roots or aerial roots. For example- orchids, banyan figs, pohutukawa trees, etc. These roots store the oxygen molecule for survival during the flood.
• The Bradyrhizobium Bacteria settles inside the root system of plants and multiplies to form root nodules. Here, the Bacteria begin to fixate nitrogen collected from the atmosphere to transform it into ammonia compounds. The redundant amount of ammonia gets absorbed by the soil so that it acts like a natural fertilizer. These bacteria are present in alfalfa, legumes, clover roots, etc. Nitrogen fixation also takes place in blue-green algae.

Types of Taproot

The tap roots are divided into three categories:

1. Conical Roots- These are the primary roots that begin to protrude from the base of the stem and then turn narrow till the end of the root tip. The one swollen end and one shrunken end appear like makes the root line of a cone. There are also thread-like secondary and tertiary roots present along with them. A large number of conical roots emerge adjacent to the large tree trunks. The function of these roots is to collect oxygen for respiration by using their pointed tips to absorb water. For example-carrot
2. Napiform Root- These are the modifications of a taproot that begins to get thick and swollen at the base of the stem like a sphere and then begin to shrink in width as they elongate like a thread. These roots grow slantly downward and deep into the soil, so they can help the plant to stand upright. The hypocotyls (the part between radicle and cotyledons that helps the taproots store food) cover most of the fleshy part in this modification. For example - turnip
3. Fusiform Root- In this modification, the root is puffed from the middle (spindle-shaped) while both ends are shriveled. Some fleshy parts are obtained from the hypocotyl, and the roots could store within them due to their presence. For example- Radish

Fibrous Roots

The fibrous root is known to be the major root of a plant. These roots do not burrow deep in the soil and begin their lifespan as adventitious roots. However, they strongly affiliate with soil particles, and this state, in turn, prevents the plants from soil erosion. Also, due to this property, they can be located near the ground's surface.

These roots are also known as Adventitious Roots, growing from the region where the stem ends. These roots can only be located in monocotyledonous plants. Later the germination of primary roots from the radicle and the parietal roots emerge from the pericycle. For example- sugarcane, bamboo, onion, etc.

When a large number of thin and similar roots in diameter and length are joined together in the form of a cluster, these are collectively known as fibrous roots. Cereal crops such as rice, maize, wheat, and pulses are mostly grow through mixed cropping. Through this farming method, many crops can be grown simultaneously, and the rows of these crops inhibit soil erosion by sheathing the uppermost layer of soil.

Functions of Fibrous Roots

• In contrast to the taproot, the fibrous root springs up from the bottom of the stem or the junctions of rhizomes.
• The thin root hairs in fibrous roots operate to absorb water and nutrients from the earth.
• Fleshy fibrous root modifications function to store food, and the roots get enlarged.
• The stilt root modification serves as the mechanical brace for the plant.

Types of Fibrous Roots

There are three categories of fibrous root systems:

1. A Tuberous Root: Is a modified root that functions as an organ where food can be stored. The root could get entirely swollen due to the storage of nutrients, or it could only get enlarged from the midriff. It shares qualities with the stem tuber regarding functions and structure. Tuberous roots' propagation occurs through crown division in mostly inactive plants. The method when the plant is not grown from the seed but splits away a small fragment of the parent plant is known as crown division. The crown is the region where the root and stems of a plant converge with one another. The root fragment should have buds on the surface for food storage. Therefore, they have also termed storage roots. For example- sweet potato, airplane plant, dahlia, etc.
2. Fasciculated Roots: A lump of swollen and unarranged roots is formed by the fasciculated roots. Their major function is to gather food inside them. For example- dahlia, asparagus, etc.
3. Annulated Roots: The inflation appears in roots that are ring-shaped. The ring-shaped swellings are arranged in stacks, one over the other, so they seem like discs, for example-grass, Ipecac, bitter gourd, etc.

Difference Between Taproot and Fibrous Root