Root Questions in English

(B) Pneumatophores are specialized respiratory roots found in plants growing in swampy or saline areas (mangroves).
These roots grow vertically upwards (negatively geotropic) to obtain oxygen for respiration.
$Avicennia$ is a classic example of a mangrove plant that exhibits pneumatophores.

(B) In Turnip,the fleshy,swollen part of the root is primarily formed by the hypocotyl.
Specifically,more than $2/3$ of the fleshy root structure is derived from the hypocotyl region of the seedling,while the remaining portion is derived from the radicle.

(A) Root hairs are tubular extensions of the epidermal cells of the root,known as epiblema or piliferous layer.
They are always unicellular structures that help in the absorption of water and minerals from the soil.
Therefore,the correct option is $A$.

(A) tap root system is the primary root that develops from the radicle of the embryo.
It exhibits positive geotropism ($+ve$ geotropic) because it grows downwards towards the center of gravity (soil).
It also exhibits positive hydrotropism ($+ve$ hydrotropic) because it grows towards the source of water in the soil.
Therefore,the correct answer is $A$.

(D) Climbing roots are adventitious roots that arise from the nodes or internodes of the stem to help the plant climb up a support.
In $Hedera$ (Ivy), $Piper$ (Betel), $Pothos$ (Money plant), $Tecoma$, and Black pepper $(Piper \text{ } nigrum)$, the roots are modified to provide mechanical support for climbing.
Therefore, all the mentioned plants exhibit this adaptation.

(D) Stilt roots are adventitious roots that arise from the lower nodes of the stem to provide mechanical support to the plant.
These roots grow obliquely downwards into the soil and act as braces to support the heavy stem.
This type of root system is characteristic of monocotyledonous plants with tall,slender stems such as $Sorghum$,$Maize$,and $Sugarcane$.
Therefore,all the given options exhibit stilt roots.

(C) In plants,the primary root originates from the radicle of the embryo.
Secondary and tertiary roots,which are branches of the primary root,originate from the pericycle layer of the stele.
Because they arise from internal tissues (pericycle) rather than the outer epidermis or cortex,they are termed endogenous in origin.
Therefore,secondary roots are stellar (arising from the stele) and endogenous in nature.

(B) In $Pandanus$ $(Screw\, Pine)$,the aerial stilt roots possess multiple and multicellular root caps. These root caps consist of several layers or sheaths,which is a characteristic feature of these plants.

(B) The root cap is a protective structure at the tip of the root. In plants like $Pandanus$ (screw pine),the root cap is exceptionally large and well-developed,often referred to as a multiple root cap. This is an adaptation to protect the root tip as it grows through the soil or in aquatic environments.

(B) The correct answer is $B$.
$Raphanus$ $sativus$ (radish) and $Daucus$ $carota$ (carrot) are examples of fleshy tap roots modified for food storage.
Radish exhibits a fusiform root shape,while carrot exhibits a conical root shape.

(D) Roots are absent in several aquatic plants due to their specific habitat and mode of nutrition.
$1$. $Myriophyllum$ is an aquatic plant that often lacks true roots.
$2$. $Ceratophyllum$ (hornwort) is a submerged aquatic plant that is rootless.
$3$. $Utricularia$ (bladderwort) is a rootless carnivorous plant.
$4$. $Wolffia$ is the smallest known flowering plant and is also rootless.
Therefore,all the mentioned plants lack roots.

(D) In fleshy tap roots,the root system is derived from the radicle of the embryo. The hypocotyl is the region of the embryonic axis between the cotyledons and the radicle. In most fleshy tap roots like the conical root of carrot $(Daucus \ carota)$,the fusiform root of radish $(Raphanus \ sativus)$,and the napiform root of turnip $(Brassica \ rapa)$,the storage of food occurs primarily in the root itself,which develops from the radicle. The hypocotyl does not contribute to the formation of the fleshy root structure in these examples. Therefore,all the mentioned types follow this pattern.

(D) Haustorial $(Parasitic)$ roots: The roots of parasitic plants,which penetrate into the host tissues to absorb nourishment,are called haustorial roots. These specialized roots allow the parasite to extract water and nutrients directly from the host plant's vascular system.

(D) The root is a vegetative part of the plant that differs from the stem in several morphological features:
$1$. Roots possess a root cap at their apex for protection,which is absent in stems.
$2$. Roots have unicellular root hairs,whereas stems may have multicellular trichomes.
$3$. Roots lack nodes and internodes,which are the characteristic features of stems.
Therefore,all the given options are correct characteristics that distinguish a root from a stem.

(D) Roots that do not develop from the radicle are known as adventitious roots.
$(a)$ Fibrous roots in grasses develop from the base of the stem,not the radicle.
$(b)$ Stilt roots in maize arise from the lower nodes of the stem.
$(c)$ Sucking roots (haustoria) in $Cuscuta$ arise from the stem to absorb nutrients from the host.
Therefore,all the given options represent adventitious roots.

(B) . Seminal roots are thread-like lateral roots that arise from the coleorhiza. In monocots,the primary root (radicle) is short-lived and degenerates early,so these seminal roots function as the primary root system during the early stages of development.

(C) The correct answer is $C$. Epiphytic roots,which are found in plants like orchids,are aerial roots that absorb moisture from the atmosphere. These roots lack both root hairs and root caps because they do not need to penetrate the soil for anchorage or water absorption.

(A) Velamen is a specialized,dead,spongy tissue found in the aerial roots of epiphytic plants like orchids.
It consists of multiple layers of empty cells that are capable of absorbing moisture directly from the atmosphere.
Therefore,it plays a crucial role in the absorption of moisture from the air.

(C) Adventitious roots are those roots that develop from any part of the plant other than the radicle. Since the radicle is the normal site of origin for the primary root,roots arising from stems,leaves,or other parts are termed 'adventitious' due to their abnormal place of origin.

(D) In $Dahlia$,the roots are fasciculated tuberous.
These are swollen adventitious roots that occur in clusters or fascicles at the base of the stem.
Unlike simple tuberous roots,these roots are found in groups,which is a characteristic feature of $Dahlia$.

(A) Pneumatophores are specialized root structures found in plants growing in swampy or saline areas,such as mangroves (e.g.,$Rhizophora$).
These roots grow vertically upwards (negatively geotropic) out of the soil or water to obtain oxygen from the atmosphere.
Therefore,they are primarily useful for the process of respiration in oxygen-deficient soil conditions.

(C) Pneumatophores are specialized roots that grow vertically upwards from the soil into the air to facilitate gaseous exchange.
These are commonly found in plants growing in swampy or saline areas,such as mangroves (e.g.,$Rhizophora$ and $Avicennia$).
In these waterlogged,oxygen-deficient soils,the roots cannot obtain sufficient oxygen,so they develop these specialized structures to breathe.
Therefore,the correct answer is $C$.

(A) The root hairs develop from the region of maturation (also known as the zone of differentiation).
In this region,some of the epidermal cells (epiblema) extend to form fine,delicate,thread-like structures called root hairs.
These root hairs are responsible for the absorption of water and minerals from the soil.
Therefore,the correct option is $A$.

(C) Haustoria are specialized parasitic roots found in parasitic plants that penetrate the host tissue to absorb nutrients and water.
$Cuscuta$ (dodder) is a total stem parasite that develops haustoria to derive nutrition from the host plant.
Betel uses climbing roots,orchids often have epiphytic roots,and Tinospora has assimilatory roots.

(D) Buttress roots are laterally compressed horizontal roots that grow along the surface of the ground for some distance.
They provide additional mechanical support to the plant,especially in large trees.
An example of a plant with buttress roots is $Ficus$ $elastica$.

(B) Velamen is a specialized,spongy,multi-layered epidermis found in the aerial roots of epiphytic plants,such as orchids.
It is hygroscopic in nature,meaning it absorbs moisture from the atmosphere,which allows the plant to survive without direct contact with soil water.

(D) Pneumatophores are specialized respiratory roots found in plants growing in swampy,saline areas,known as $Halophytes$ (e.g.,$Rhizophora$).
These roots grow vertically upwards (negatively geotropic) out of the soil to obtain oxygen for respiration,as the soil in these areas is often waterlogged and oxygen-deficient.

(D) The correct answer is $(d)$.
Roots that develop adventitious buds and participate in vegetative propagation are known as reproductive roots.
In plants like $Dalbergia$ $(Shisham)$,$Dahlia$,and $Sweet$ $Potato$ $(Ipomoea)$,the roots possess the ability to produce new plantlets from adventitious buds.
Therefore,all the given examples represent plants with reproductive roots.

(D) $(1)$ Assimilatory roots (e.g.,Tinospora) perform photosynthesis.
$(2)$ Fasciculated roots (e.g.,Dahlia) are used for food storage.
$(3)$ Stilt roots (e.g.,Maize,Sugarcane) provide mechanical support.
$(4)$ Sucking roots (Haustoria) are found in parasitic plants like Cuscuta,which penetrate the host to absorb nutrients,not moisture from the air (which is the function of Velamen roots in epiphytes).
Therefore,pairs $(1)$,$(2)$,and $(3)$ are correctly matched.

(D) $Velamen$ is a specialized,spongy,multi-layered epidermis found in the aerial or hanging roots of epiphytic plants like $Vanda$.
These roots hang freely in the air and are not attached to the soil.
The $velamen$ tissue is hygroscopic in nature,which allows the plant to absorb moisture directly from the humid atmosphere and rain,compensating for the lack of soil contact.

(B) The root is organized into different regions starting from the tip towards the base:
$1$. Root cap: Protects the tender apex of the root.
$2$. Region of meristematic activity (Cell division zone): Located a few millimeters above the root cap,where cells divide rapidly.
$3$. Region of elongation: Located proximal to the meristematic zone,where cells undergo rapid elongation and enlargement,responsible for the growth of the root in length.
$4$. Region of maturation: Located proximal to the elongation zone,where cells differentiate and mature. Root hairs are found in this region.
Therefore,when moving from the base (proximal) to the root tip (distal),the order is Maturation zone — Elongation zone — Cell division zone.

(B) $Vanda$ is an epiphytic orchid that grows on other plants for support. It possesses specialized aerial roots containing a spongy tissue called $velamen$. The $velamen$ is a multi-layered epidermis that absorbs moisture directly from the atmosphere,allowing the plant to survive in humid environments without being rooted in soil.

(A) Hygroscopic roots,also known as epiphytic roots,are found in epiphytic plants like $Vanda$.
These roots possess a specialized spongy tissue called $velamen$,which absorbs moisture directly from the atmosphere.
$Rhizophora$ exhibits pneumatophores (respiratory roots),and $Bryophyllum$ reproduces through foliar buds (leaf buds).
Therefore,the correct answer is $Vanda$.

(C) In plants,the primary root is formed from the radicle of the embryo. Roots that develop from any part of the plant other than the radicle are called adventitious roots. Examples include roots arising from stems or leaves.

(C) Grasses possess a fibrous root system that spreads extensively in the soil.
These roots form a dense network that binds the soil particles together,which is highly effective in preventing soil erosion.
Therefore,soil binding roots are characteristic of grasses.

(B) $Mirabilis \text{ } jalapa$ exhibits a modified tap root system. In this plant, the tap root becomes thickened and fleshy to store food, but it does not possess a definite shape. This type of root modification is known as a tuberous root.

(A) The $Fusiform$ root is swollen in the middle and tapers towards both the apex and the base, resembling a spindle shape.
Examples include radish $(Raphanus \text{ } sativus)$.
$Conical$ roots are broad at the base and taper gradually towards the apex (e.g., carrot).
$Napiform$ roots are very broad at the base and suddenly taper like a tail at the apex (e.g., turnip).
$Tuberous$ roots do not have a regular shape.

(B) The correct answer is $B$.
Fibrous roots are thin,thread-like adventitious roots that develop in large groups from the base of the stem.
Because they spread extensively in the upper layers of the soil,they provide a much larger surface area for anchorage,which helps in holding the plant firmly to the soil,especially in grasses.

(D) Chloroplasts are absent in root hairs because root hairs are located underground and do not perform photosynthesis. Their primary function is the absorption of water and minerals from the soil.

(C) Pneumatophores are specialized respiratory roots found in plants growing in swampy or saline areas.
These roots grow vertically upwards (negatively geotropic) from the horizontal underground roots to obtain oxygen.
They bear small pores called lenticels or pneumathodes,through which the exchange of gases occurs.
Example: $Rhizophora$.

(D) The correct answer is $D$.
Prop roots are adventitious roots that grow downwards from the branches of the Banyan tree $(Ficus \text{ } benghalensis)$ to provide mechanical support to the heavy spreading branches.
These roots eventually reach the soil, become thick, and look like additional trunks.
For example, a single Banyan tree in the Indian Botanic Garden, Sibpur, Howrah, covers an area of $200 \text{ } \text{acres}$ and possesses over $1600 \text{ } \text{prop roots}$.

(C) The correct answer is $C$.
In epiphytic plants,such as orchids,the roots are specialized to absorb moisture directly from the atmosphere.
These roots possess a specialized,multi-layered,spongy tissue on their exterior known as the velamen.
This tissue acts like a sponge,absorbing water vapor and nutrients from the surrounding air,which is essential for the survival of epiphytes that grow on other plants.

(C) $Raphanus \text{ } sativus$ belongs to the family $Brassicaceae$ (formerly $Cruciferae$).
Its roots and leaves are commonly consumed as vegetables.

(D) The term 'plantless root' refers to plants where the vegetative body is reduced to a root-like structure,and the shoot system only develops for the purpose of flowering. In plants such as $Arceuthobium$,$Podostemon$,$Rafflesia$,and $Sapria$,the main plant body is highly modified or reduced,often appearing as a root-like thallus,while the shoot only emerges to produce flowers. Therefore,all the given options represent plants that exhibit this characteristic.

(D) $Pistia$ is a free-floating aquatic plant.
These plants possess one or more adventitious roots that hang downward into the water.
The primary function of these roots in such floating plants is to provide stability and balance to the plant body on the water surface.
Therefore,the correct option is $D$.

(A) deep feeder root system is also known as a $Racemose$ tap root system.
In this type of system, the primary or tap root grows deep into the soil and is long, while the lateral branches are comparatively shorter.
This arrangement allows the plant to access water and nutrients from deeper soil layers.
Examples include plants like $Mango$ $(Mangifera \text{ } indica)$ and $Peepal$ $(Ficus \text{ } religiosa)$.

(C) The multiseriate epidermis found in the aerial roots of certain orchids and epiphytes is known as velamen.
This tissue is specialized for the absorption of atmospheric moisture.
The layer that acts as a boundary or separation between the velamen and the underlying cortex is known as the exodermis.
Therefore,the correct option is $C$.

(C) $Velamen$ is a specialized,multi-layered spongy tissue found in the aerial roots of epiphytic plants like orchids.
Its primary function is the absorption of moisture from the atmosphere and humidity,which helps the plant survive in environments where water is not directly available from the soil.
Therefore,the correct option is $C$.

(D) The root apex is considered subterminal because the actual meristematic region is protected by a multicellular structure known as the root cap.
Since the root cap covers the delicate apical meristem,the meristem itself is located slightly behind the very tip of the root,making it subterminal.

(D) The correct answer is $D$.
In the root apex, the $calyptrogen$ is a specialized layer of meristematic cells that gives rise to the $root cap$.
The $root cap$ is a thimble-like structure that covers the tender apex of the root, protecting it from the friction of the soil particles as it grows through the ground.