Plant Root Systems - Types, Modifications, and Anatomy

The monocotyledonous plants possess the adventitious or the fibrous type of root system. There are many fine thread-like branches which develop from any other part of the plant rather than the radicle. These type of roots do not grow much deeper but spread in the region widely to provide support the plant.

Plants that grow completely inside water and their roots are affixed to the soil under water with their leaves, stems and existing blooms of a plant are also submerged under normal water level.

The of tap roots is said to be towards gravity because the tap roots grow downward into the ground to absorb water and nutrients from deeper parts of the soil.

Adventitious roots are the type of roots that are grown from different parts of plants such as stem, leaf and tubers etc. These are used in vegetative propagation.
Correct option is C.

Stem the supportive and holding part of a plant that grows from plumule and attracts towards a light and normally grows above the ground and considered to be negatively geotropic.

• Stilt roots are adventitious roots. They arise from the lower nodes of stem and enter the soil and become stronger. They help in the anchorage. 
• For example, maize and sugarcane. So, the correct answer is 'Adventitious Root'.

Fusiform root is those roots, which are swollen from middle and narrow towards the bottom parts. 

So, the correct answer is ' Raphanus sativus '

Fasciculated roots is a modified adventitious root.

• These roots are either swollen or they form root tubers in clusters.

• Eg- Dahlia and Asparagus.

• In Dahlia, these swollen roots lie at the base of the stem whereas, in Asparagus the swollen roots occur at intervals on the roots.

• So, the correct answer is 'Dahlia'.

Stilt root is an adventitious root, which develops from the basal nodes present on the main axis. This type of root provides mechanical support to the plant. 

So, the correct answer is  ' Pandanus (screwpine) '.

Fibrous roots are highly branched roots and have more root hairs as well as more surface area than a taproot system. Due to more surface area, fibrous root helps the plants of anchorage to soil very firmly. So, the correct answer is 'Anchorage of plant to soil'.

Fasciculated roots are found in Dahlai and Asparagus.  The fasciculated roots are tuberous roots arising from the stem base in clusturs. 

The common feature between Pinus, Monotropa and Sarcodes is mycorrhizal roots. Mycorrhizae form a mutualistic relationship with the roots of most plant species. Most plant families are predominantly mycorrhizal. This mutualistic association provides the fungus with relatively constant and direct access to carbohydrates. The carbohydrates are translocated from their source to root tissue and onto the plant's fungal partners. In return, the plant gains the benefits of the mycelium's higher absorptive capacity for water and mineral nutrients due to the comparatively large surface area of mycelium, thus improving the plant's mineral absorption capabilities.

Radish is an example of fusiform tap root. The edible part of radish is a modified tap root. In a plant with a taproot system, the taproot is the central and dominant root. Typically, a taproot is straight and very thick. It is tapering in shape and grows directly downward. There are different types of modified tap roots like fusiform, napiform, conical, tuberous roots. Fusiform root is swollen at the middle and tapers gradually at both the ends forming a spindle shaped structure.
Therefore, the correct answer is option D.

Roots growing from any part of plant other than the original root system are termed as adventitous roots. Adventitious roots arise out of sequence from the more usual root formation of branches of a primary root and instead originate from the stem, branches, leaves or old woody roots. They commonly occur in monocots and pteridophytes. Most aerial roots and stilt roots are adventitious. In some conifers, adventitious roots can form the largest part of the root system.
Thus, the correct answer is option A.

Modified aerial adventitious roots which develop from lower part of the stem node for mechanical support are called as stilt roots. Stilt roots arise from basal nodes of the stem near the soil. Stilt roots are generally present in plants growing in loose sandy soils. As the normal roots are not properly fixed, these modified roots enter obliquely into soil and act as supporting organs. For example, Zea mays (maize). 

Vetiveria is the common name for the plant Chrysopogon zizanioides, one of the fragrant grass varieties. The roots of this plant stores an aromatic oil that is used in skin treatment and in aromatherapy. The aromatic oil extracted from the roots of Chrysopogon zizanioides is known as khus oil.
Thus, the correct answer is option C.

Tuberous roots are found in Ipomoea batatas. A tuberous root or storage root is a modified lateral root which is enlarged to function as a storage organ. The enlarged area of the storage root can be produced at the end or middle of a root or involve the entire root. It is thus different in origin but similar in function and appearance to a stem tuber. Examples of plants with notable tuberous roots include the sweet potato, Cassava, and Dahlia. The sweet potato (Ipomoea batatas) is a dicotyledonous plant that belongs to the family Convolvulaceae. Its large, starchy, sweet-tasting, tuberous roots are a root vegetable. The young leaves and shoots are sometimes eaten as greens.
Thus, the correct answer is option C.

Stilt root occur in sugarcane. These are adventitious support roots which are common among mangroves. They grow down from lateral branches, branching in the soil. Stilt roots arise from the first few nodes of the stem. The stilt root penetrates down into the soil. It gives support to the plant. For example, maize and sugarcane.
Thus, the correct answer is option C.

In dicot roots, the pith is either absent or not well developed. On the other hand in case of monocot root, we find a well developed pith across all the genera.
Thus, the correct answer is option C.

Grasses are the monocotyledonous plants. These plants possess the adventitious or the fibrous type of root system. There are many fine thread-like branches which develop from any other part of the plant rather than the radicle. These type of roots do not grow much deeper but spread in the region widely to provide support the plant.

The monocotyledonous plants possess the adventitious or the fibrous type of root system. There are many fine thread-like branches which develop from any other part of the plant rather than the radicle. These type of roots do not grow much deeper but spread in the region widely to provide support the plant.

Adventitious roots do not arise from the radical of the seed. Instead, they can originate from the plumule parts such as stem, branches, leaves, or old woody roots of the plants. Hence, they are termed as adventitious. They commonly occur in monocots and pteridophytes. 

The adventitious roots found in the epiphytes are known as the epiphytic root. These roots hang freely in the air and absorb the moisture from the air by a special type of tissue called as velamen. Epiphytic plants are sometimes called as air plants because, they do not have roots in the soil. For example, Vanda.

Sweet potato and turnip are root modifications. Sweet potato is a type of adventitious roots, which is modified to store food materials. The edible tuberous root is long and tapered. Turnip is a type of tap root. Ginger, potato, Colocasia are underground stem modifications for food storage. Both have the same function but different structure and thus are called as homologous.

When the adventitious roots modified for aerial support is called as prop roots. Prop roots give mechanical support to the aerial branches. The lateral branches grow vertically downward into the soil and act as pillars. Prop or pillar or columnar roots are pillar-like roots which give extra mechanical support to heavy stem branches, e.g., banyan tree. 

Vegetative propagation by roots takes place in modified roots called as tubers. Buds grow from the base of the stem into new plants. These roots are swollen for food storage. For example, Sweet potato, Asparagus, Tapioca and Dahlia.

Fasciculated roots are the type of modified adventitious root. They are tuberous root which become thick due to storage of food. These types of roots occur in clusters from the base of the stem, e.g., Asparagus, Tapioca, Dahlia.

Statement I is correct (monocots have fibrous roots). Statement III is correct (sweet potato roots store food). Statement II is wrong (root hair zone is behind the elongation zone). Statement IV is wrong (prop roots are in Banyan, not Maize/Sugarcane; those are stilt roots).

Adventitious roots arise from parts of the plant other than the radicle. Among the listed plants, Maize, Sugarcane, and Onion all develop adventitious roots, while Carrot has a taproot system (modified taproot). Therefore, exactly 3 of the listed plants have adventitious roots.

Statement a is correct (anatomy is similar). Statement b is correct (dicot stem hypodermis is collenchymatous, but some sources classify it as sclerenchymatous in specific contexts, though usually collenchyma). Wait, statement d is correct (dicot leaves are dorsiventral and hypostomatic). Given the options, 1 and 2 are the most likely intended correct pair.

Assimilatory roots (e.g., Tinospora) perform photosynthesis. Fasciculate roots (e.g., Dahlia) store food. Stilt roots (e.g., Maize) provide mechanical support. Sucking roots (e.g., Cuscuta) are haustoria for absorption from host plants, not moisture from air (that is velamen roots).

Moniliform or beaded roots are adventitious roots which are swollen at regular intervals like beads of a necklace. For example, Baseila rubra (India spinach), Momordica and some grasses.

Raphanus sativus is an edible root vegetable of the Brassicaceae family. It has a fusiform taproot system. The edible part of radish is a modified tap root. Radishes are eaten as a salad vegetable. 

Growth of tap roots is towards gravity. Typically, a taproot is very thick. It is tapering in shape and grows directly downward into the soil towards the force of gravity. In plants with taproot systems, the taproot is the central root from which other roots sprout laterally.
Thus, the correct answer is option A.

The drug belladona is obtained from roots of Atropa belladona. Atropa belladonna, commonly known as belladonna or deadly nightshade, is a perennial herbaceous plant in the family Solanaceae. The foliage and berries are extremely toxic, containing tropane alkaloids. These toxins include scopolamine and hyoscyamine, which cause a bizarre delirium and hallucinations.

Dicot root shows secondary growth in thickness. Dicot root possess 2-4 xylem and phloem patches. These patches are separated by parenchymatous cells. The parenchymatous tissue present in between xylem and phloem become meristematic in later stages. These are called as cambium ring. 

Plant roots are so designed that it can take up water and nutrients from the soil and pass it on to the shoot. At the same time, there are chances of  unwanted and toxic compounds be also taken along with any soilborne pathogens. To protect the roots from such intake, specific unicellular tissues, such as exodermis is located at the outer surface of the root directly below the root epidermis.
Thus, the correct answer is option C.

Screwpine shows stilt roots because the stem of the plant is weak and needs additional support to withhold the erect structure by arising roots from the lower nodes.

Banyan Trees are having a supporting root system for its branches. But maize and sugarcane have the stilt root to help the plant to stand erect. Prop roots or columnar roots in banyan. These aerial roots appear like props or columns. 

In banyan tree, these roots develop from the large, horizontal branches of large trees. Stilt roots in maize and Sugarcane are adventitious. They are developed from the lower part of the stem and grow obliquely. The stilt roots give additional support to the plants.

The correct options are i and ii.

Thus the correct option is D.