Root Questions in English

(C) The primary root and its branches constitute the tap root system.
In dicotyledonous plants,the primary root is formed from the elongation of the radicle and continues to grow to form the tap root.
In contrast,monocotyledonous plants typically possess an adventitious root system where roots arise from parts of the plant other than the radicle.

(B) $Rafflesia$ is a holoparasitic plant. It lacks chlorophyll and cannot perform photosynthesis. The tip of its root forms haustorial connections with the roots of the host plant (typically $Tetrastigma$ vines) to absorb water and nutrients. Therefore,it is classified as a total root parasite.

(B) In $Orchid$,many short,branched,adventitious roots arise at each node of the weak stem to help the plant climb up its support; these are called clinging roots.

(A) The root hairs are unicellular extensions of the epidermal cells of the root. They significantly increase the surface area available for the absorption of water and mineral salts from the soil. Therefore,root hairs are the primary sites for water absorption.

(B) The correct answer is $B$.
Pneumatophores are specialized respiratory roots found in plants growing in saline marshy areas (mangroves).
In these environments,the soil is often waterlogged and oxygen-deficient.
To overcome this,some branches of the tap root grow vertically upwards into the air from the horizontal secondary roots to facilitate gaseous exchange.
These specialized roots are known as pneumatophores.

(C) Roots that develop from any part of the plant other than the radicle are known as adventitious roots. In many plants,especially monocots,the primary root (derived from the radicle) is short-lived and is replaced by roots originating from the stem,nodes,or leaves.

(A) In $Hydrophytes$,the root system is poorly developed or reduced because these plants obtain water and nutrients directly from the surrounding aquatic environment through their body surface. In many floating $Hydrophytes$,roots are very small,and in some submerged $Hydrophytes$,roots may be completely absent.

(A) The roots of leguminous plants,which belong to the family $Fabaceae$ (formerly $Leguminosae$),often develop small,spherical swellings known as root nodules.
These nodules are formed due to the symbiotic association between the plant roots and nitrogen-fixing bacteria such as $Rhizobium$.
Among the given options,$Pea$ ($Pisum$ $sativum$) is a member of the family $Fabaceae$,and therefore,it exhibits nodulated roots.
Wheat,Mustard,and Rice are not leguminous plants and do not form root nodules.

(C) The root cap is a thimble-like,parenchymatous,multicellular structure that covers the root apex.
As the root grows downwards into the soil,it faces friction with soil particles.
The root cap protects the delicate root meristem from this mechanical injury.
Its outer cells are constantly worn away and replaced by new cells produced by the meristematic activity at its base.

(D) Conical roots are a type of fleshy taproot modification.
In these roots,the base is broad and tapers gradually towards the apex,giving it a cone-like shape.
Carrot $(Daucus \ carota)$ is the classic example of a conical root.
Sweet potato is a tuberous root,Dahlia is a fasciculated root,and Asparagus is a fasciculated root.

(C) $Napiform$ roots are characterized by a base that is much swollen and nearly globular or spherical in shape,which then suddenly tapers towards the apex,giving it a top-shaped appearance.
Examples of plants with $Napiform$ roots include $Turnip$ ($Brassica$ $rapa$) and $Beet$ ($Beta$ $vulgaris$).
Therefore,the correct option is $C$.

(D) Fusiform roots are a type of modified tap root that is swollen in the middle and tapers gradually towards both the base and the apex, resembling a spindle shape.
This type of root is characteristic of $Raphanus \text{ } sativus$ (radish).
In contrast, $Daucus \text{ } carota$ (carrot) exhibits conical roots, while $Solanum \text{ } tuberosum$ (potato) and $Colocasia$ exhibit stem tubers.

(B) The $Tap \text{ } root \text{ } system$ is a type of root system in which the primary root, which develops directly from the $radicle$ of the embryo, forms the dominant central axis.
This central axis is known as the $tap \text{ } root$, which bears lateral branches of various orders, such as secondary roots, tertiary roots, and rootlets.

(A) In some plants,roots arise from the lower nodes of the stem and enter the soil to provide extra support.
These roots behave like the ropes of a tent. Such roots are called stilt or brace roots. Examples include $Pandanus$ (screw pine) and $Zea$ $mays$ (maize).

(C) Assimilatory or photosynthetic roots are specialized roots that contain chlorophyll and are capable of performing photosynthesis.
These roots synthesize carbohydrates from carbon dioxide and water in the presence of sunlight.
Examples of plants exhibiting this adaptation include $Trapa$, $Tinospora$, $Taeniophyllum$, and $Podostemon$.

(D) Roots are the underground parts of the plant body that lack nodes and internodes.
Nodes and internodes are characteristic features of the stem.
Therefore,roots do not bear nodes or internodes.

(B) Root pockets are modified root caps found in free-floating aquatic plants.
They serve the function of balancing the plant in water.
Unlike root caps,root pockets cannot be regenerated if damaged.
Examples include $Pistia$,$Eichhornia$,and $Lemna$.

(C) The primary function of a root is the absorption of water and minerals from the soil.
In the case of $B$ (Conical roots of carrot),the root is modified for the storage of food,but it still performs the primary function of absorption.
In $A$ (Nodulated roots of gram),the roots perform nitrogen fixation but also continue to absorb water and minerals.
In $D$ (Stilt roots of maize),the roots provide mechanical support but also absorb water and minerals.
However,in $C$ (Buttress roots of $Ficus$),these are aerial roots that provide structural support to the tree. While they are modified for support,they do not perform the primary function of absorbing water and minerals from the soil as they are often aerial or superficial,and the plant relies on other root systems for absorption.

(B) In monocotyledonous plants,the primary root is short-lived and is replaced by a large number of roots that originate from the base of the stem.
These roots constitute the fibrous root system,which is a characteristic feature of monocots (e.g.,wheat,rice).
In contrast,tap roots are characteristic of dicotyledonous plants.

(A) Epiphytic roots are specialized aerial roots found in epiphytes,such as $Orchid$,which grow on other plants for support but do not derive nutrients from them. These roots are often green and photosynthetic,and they possess a specialized tissue called $velamen$ to absorb moisture from the atmosphere. Clinging roots are adventitious roots that help climbing plants attach to a support,commonly seen in $Pothos$ (money plant) and $Hedera$ (ivy).

(C) Stilt roots are adventitious roots that provide mechanical support to the plant. In $Pandanus$ $(Screw\, pine)$,these roots arise from the lower nodes of the obliquely growing stem to support the plant and prevent it from falling over.

(A) In $Ipomoea\, batatas$ (Sweet potato),the adventitious roots become swollen and fleshy due to the storage of food materials. These are known as root tubers. Unlike stem tubers,they do not have nodes or internodes and arise from the roots.

(A) In maize $(Zea \, mays)$, the roots that develop from the lower nodes of the stem are known as stilt roots. These are a type of adventitious root that provides additional support to the plant, helping it remain upright in the soil. These roots are fibrous in nature and arise from the basal nodes of the stem.

(B) The correct answer is $B$.
In nearly all dicotyledonous plants,the direct elongation of the radicle leads to the formation of the primary root,which is also known as the $Tap$ root system.
This primary root grows inside the soil and bears lateral roots of several orders.

(C) The edible part of the sweet potato $(Ipomoea \text{ } batatas)$ is the adventitious root. These roots become swollen and fleshy to store food material, which is why they are consumed as a vegetable.

(B) Leguminous plants belong to the family $Fabaceae$.
These plants have a symbiotic relationship with nitrogen-fixing bacteria such as $Rhizobium$.
These bacteria reside in small swellings on the roots known as root nodules.
Therefore,leguminous plants possess nodulated roots which help in biological nitrogen fixation.

(D) Stilt roots provide extra support to the long,unbranched stem of plants like maize and sugarcane. They do not store food. In contrast,tuberous,napiform,and conical roots are modifications of the taproot or adventitious roots specifically adapted for food storage.

(C) Epiphytic roots are found in epiphytes like $Vanda$.
These roots hang freely in the air and possess a specialized spongy tissue called $velamen$.
$Velamen$ is hygroscopic in nature,which allows the plant to absorb moisture and humidity directly from the atmosphere.
These roots are typically devoid of root hairs and root caps.

(D) The adventitious roots help the plant in climbing by penetrating the cracks of the support. These are known as climbing roots. Examples include $Piper$ $betle$ (betel vine) and $Pothos$.

(B) Sweet potato $(Ipomoea \text{ } batatas)$ is a modified adventitious root.
These roots become swollen and fleshy to store food, which is a characteristic feature of tuberous roots.

(D) is the correct answer. Potato is a modification of an underground stem (tuber),whereas sugarbeet,carrot,and radish are examples of modified taproots that store food.

(A) Aerial absorptive roots,also known as velamen roots,are specialized roots found in epiphytes (plants that grow on other plants for support).
These roots hang in the air and possess a spongy tissue called velamen,which absorbs moisture from the atmosphere.
Therefore,the correct answer is $A$.

(C) Balancing roots are specialized adventitious roots found in certain free-floating aquatic plants.
These roots hang down into the water column and help in maintaining the balance and stability of the plant body on the water surface.
Examples of plants possessing balancing roots include $Lemna$ and $Pistia$.

(A) Climbing roots are specialized adventitious roots that help a plant climb up a support.
In the genus $Vanilla$ (an orchid),the plant produces climbing roots from the nodes to attach itself to the bark of trees or other supports,allowing it to grow upwards towards sunlight.
$Vanda$ possesses epiphytic roots,$Pongamia$ is a tree with normal root systems,and $Taeniophyllum$ is a leafless orchid with photosynthetic roots.

(D) The correct answer is $D$.
Some angiosperms,particularly certain aquatic and parasitic species,lack true roots.
$Cuscuta$ is a parasitic plant that lacks roots and absorbs nutrients through haustoria.
$Balanophora$ is a root parasite that also lacks functional roots.
$Utricularia$ (bladderwort) is an aquatic insectivorous plant where some leaves are modified into root-like structures to perform the functions of roots,as it lacks true roots.
Therefore,all the listed plants are examples of rootless angiosperms.

(B) $Cuscuta$ is a total stem parasite.
The parasite develops haustorial roots which penetrate the host tissue.
These roots establish a connection with both the xylem and phloem of the host to withdraw water,minerals,and organic food.

(A) Pneumatophores or respiratory roots are specialized upright,aerial,and negatively geotropic roots.
These roots emerge from the soil to facilitate gaseous exchange in oxygen-deficient,waterlogged,or saline environments.
They are commonly found in mangrove plants such as $Sonneratia$ and $Heritiera$.

(D) The correct answer is $D$.
Haustorial roots,also known as parasitic or sucking roots,are a modification of adventitious roots found in parasitic plants.
These roots penetrate the tissues of the host plant to absorb water and nutrients directly from the host's vascular system.

(B) Orchids are epiphytes that grow on other plants for support.
They possess specialized aerial roots known as velamen roots or assimilatory roots.
These roots contain a spongy tissue called velamen,which helps in absorbing moisture from the atmosphere.
Since these roots contain chlorophyll,they are capable of performing photosynthesis,hence they are called assimilatory roots.

(D) The correct answer is $D$.
Epiphyllous roots are a type of adventitious root that develops directly from the leaf tissue.
In plants like $Begonia$ and $Bryophyllum$,these roots arise from the notches or injured parts of the leaves to facilitate vegetative propagation.
Therefore,they are defined as roots arising from leaves.

(C) Pneumatophores are specialized respiratory roots that grow vertically upwards (negatively geotropic) to obtain oxygen from the atmosphere.
These are commonly found in halophytes,which are plants growing in saline swamps or mangrove areas near the sea shore.
Among the given options,the family $Rhizophoraceae$ (e.g.,$Rhizophora$) is well-known for exhibiting pneumatophores.

(D) Prop roots, also known as pillar roots or columnar roots, are specialized adventitious roots that grow downwards from the horizontal branches of the tree.
These roots eventually reach the ground and thicken to become pillar-like structures.
Their primary function is to provide additional mechanical support to the heavy, spreading branches of the Banyan tree $(Ficus \text{ } benghalensis)$.
Therefore, the correct option is $D$.

(C) In $Pothos$ $armatus$,$Acanthorhiza$,and $Iriartea$,some adventitious roots arising from the base of the stem become hard,pointed,and thorn-like.
These modified structures are known as root-thorns.

(D) Sucking roots,also known as haustoria,are specialized roots found in parasitic plants.
$(d)$ In $Viscum$ $(Mistletoe)$,which is a hemiparasite containing chlorophyll,these roots penetrate the host plant and establish a connection with the xylem of the host to absorb water and minerals only.

(C) The correct answer is $C$.
Fasciculated roots are a type of adventitious root system where the roots become fleshy and swollen due to the storage of food.
These roots occur in clusters at the base of the stem.
Examples include $Dahlia$,$Ruellia$,and $Asparagus$.

(D) Floating roots are white,spongy,and arise from the nodes of the stem to store air.
These roots assist in buoyancy (floatation) and also facilitate gaseous exchange (breathing).
An example of a plant possessing such roots is $Jussiaea$.

(C) Prop roots, also known as pillar roots, are specialized roots that grow downwards from the branches of a plant to provide additional support to the stem.
These roots originate from parts of the plant other than the radicle, which classifies them as $Adventitious$ $roots$.
An example of a plant exhibiting prop roots is the $Banyan$ $tree$ ($Ficus$ $benghalensis$).

(D) Photosynthetic roots,also known as assimilatory roots,are green roots capable of performing photosynthesis.
In $Tinospora$ (a climbing shrub),the adventitious roots hang down from the stem and turn green upon exposure to sunlight,thereby performing photosynthesis.
$Jussiaea$ possesses floating roots for buoyancy.
$Rhizophora$ possesses pneumatophores for respiration.
$Bryophyllum$ reproduces vegetatively through leaf buds.

(D) Root pockets are specialized structures found in many aquatic plants instead of root caps.
These are loose,thimble-shaped,or elongated cap-like coverings over the root tips.
They provide protection to the root tips in an aquatic environment.
An example of a plant possessing root pockets is Water Hyacinth $(Eichhornia)$.