Permanent Tissue Questions in English

(B) Fibre cells are a type of sclerenchyma tissue. They are typically thick-walled,elongated,and possess tapering ends. These cells provide mechanical support to the plant body.

(C) Callose is a polysaccharide $( \beta-1,3-glucan )$ that is commonly deposited in the sieve areas of sieve tubes in the phloem tissue.
These deposits often form during the maturation of sieve elements or in response to injury to seal off the sieve pores.
Therefore, callose deposition is characteristically found in the sieve areas.

(C) The correct answer is $C$.
Sieve tube elements are specialized cells of the phloem tissue that are responsible for the translocation of food.
In their mature stage,sieve tube elements lose their nucleus and many other organelles to facilitate the efficient flow of materials.
However,they remain living because they maintain a close association with companion cells,which provide them with metabolic support.

(C) Xylem is a complex permanent tissue that functions primarily in the conduction of water and minerals from roots to the rest of the plant.
The secondary cell walls of xylem elements,particularly tracheids and vessels,are thickened with a complex polymer called $Lignin$.
$Lignin$ provides structural support and mechanical strength to the xylem,allowing it to withstand the negative pressure generated during transpiration.
Therefore,the cell wall of xylem cells is rich in $Lignin$.

(B) The term 'tissue' was coined by the French anatomist and physiologist $Marie \ Francois \ Xavier \ Bichat$ in $1801$.
However,in the context of plant biology,$Nehemiah \ Grew$ is often associated with the study of plant tissues,and $Carl \ Wilhelm \ von \ Nageli$ made significant contributions to the classification of plant tissues.
Given the standard options provided in many biology textbooks,$Bichat$ is the correct historical figure,but since he is not listed,the question likely refers to the botanical context where $Grew$ is often cited for his early work on plant anatomy.

(D) Matured tissues,specifically those that have undergone differentiation,exhibit several distinct characteristics.
$1$. They often develop thick cell walls (e.g.,secondary cell walls in xylem or sclerenchyma).
$2$. As cells mature,the cytoplasm becomes less dense and often contains large vacuoles,but in many specialized mature tissues,the metabolic activity decreases,leading to a reduction in cytoplasmic volume.
$3$. The nucleus in highly differentiated or mature cells often becomes smaller or may even disappear (as in sieve tube elements or mature tracheary elements).
Therefore,all the listed options are characteristic features of matured tissues.

(A) The cells produced by meristematic tissues undergo differentiation to form permanent tissues. Parenchyma is the most simple and least specialized permanent tissue,which is formed directly from the meristematic cells through the process of maturation and differentiation.

(A) simple permanent tissue is composed of only one type of cells.
These cells are structurally and functionally similar and perform a common function.
Examples include parenchyma,collenchyma,and sclerenchyma.

(C) Permanent tissues are composed of cells that have attained maturity and have lost the ability to divide. These cells are derived from meristematic tissues and are specialized to perform specific functions in the plant body.

(C) Permanent tissues are composed of cells that have lost the ability to divide. These cells have reached their final shape,size,and function. In the cell cycle,these cells exit the active cycle and enter a quiescent stage known as the $G_0$ phase (or they are arrested at the $G_1$ stage),where they perform specialized functions instead of undergoing mitosis.

(A) . Parenchyma cells are thin-walled and living cells that form the ground tissue in plants.
$B$. Collenchyma cells have uneven thickenings of cellulose,hemicellulose,and pectin at the corners.
$C$. Fibres are elongated,lignified,and thick-walled cells providing mechanical support.
$D$. Sclereids are extremely thick-walled,dead cells with narrow cavities (lumens).
Therefore,$Parenchyma$ is the tissue that does not have specifically thickened walls.

(B) $Parenchyma$ is the most common simple permanent tissue in plants. It consists of relatively unspecialized cells with thin cell walls made of cellulose. These cells are living at maturity and are responsible for various functions such as photosynthesis, storage, and secretion. Because of their thin walls and lack of secondary thickening, they form the soft parts of the plant body, such as the pith, cortex, and mesophyll.

(C) The parenchyma cells are the most common simple permanent tissue in plants.
In a packed tissue,a typical parenchyma cell is generally isodiametric in shape,meaning its dimensions are equal in all directions.
Geometrically,when these cells are packed together,they often take the shape of a $14$-sided polyhedron known as a $Tetrakaidecahedron$ to minimize surface area and maximize packing efficiency.

(C) The term 'parenchyma' was coined by the English botanist $Nehemiah \ Grew$ in his work 'The Anatomy of Plants' $(1682)$. He used this term to describe the ground tissue or the soft,succulent tissue found in plants.

(B) typical parenchyma cell,when packed in a tissue,often takes the shape of a tetrakaidecahedron (a $14$-sided polyhedron). This geometry allows for efficient space-filling in plant tissues. Therefore,a parenchyma cell is considered to have $14$ facets.

(D) Parenchyma is considered a fundamental tissue because it is the most basic and least differentiated plant tissue.
$1$. Physiologically and morphologically,it serves as the ground tissue from which other tissues are derived.
$2$. Phylogenetically,it is the most primitive type of tissue found in plants.
$3$. It acts as the progenitor or precursor for all specialized tissues like collenchyma and sclerenchyma.
Therefore,all the given statements are correct.

(C) Parenchyma is the most common type of permanent tissue found in almost all plants.
It consists of relatively unspecialized cells with thin cell walls made of cellulose.
These cells are living and perform various functions such as photosynthesis,storage,and secretion.
They form the major component within organs like leaves,stems,and roots.

(A) Parenchyma cells that contain chloroplasts are known as $chlorenchyma$.
These cells are primarily found in the leaves of plants and are specialized for the process of photosynthesis.

(B) $Collenchyma$ provides mechanical support, tensile strength, elasticity, and flexibility to the growing parts of the plant, such as young stems and petioles of leaves. It allows for easy bending without breaking, thus protecting the plant from damage due to wind or swaying.

(B) Collenchyma is a simple permanent tissue that provides mechanical support to the growing parts of the plant,such as young stems and petioles of leaves.
It is characterized by the deposition of cellulose,hemicellulose,and pectin at the corners of the cells.
Unlike Sclerenchyma,Collenchyma is never lignified,which makes it flexible and allows for the growth of plant organs.

(A) Collenchyma is a type of simple permanent tissue found in plants.
It consists of cells that are elongated in shape.
These cells possess uneven cell wall thickenings,which are primarily composed of cellulose,hemicellulose,and pectin.
These thickenings are characteristically located at the corners where the cells meet,providing mechanical support to growing parts of the plant.

(C) . Collenchyma is a type of simple permanent tissue that provides mechanical support to the growing parts of the plant,such as young stems and petioles of leaves. The cells of collenchyma are characterized by uneven thickening of their cell walls,which is primarily due to the deposition of cellulose,hemicellulose,and pectin at the corners of the cells.

(B) Sclerenchyma cells are characterized by thick,lignified secondary cell walls.
During the development of these cells,the deposition of lignin starts from the primary cell wall and progresses towards the secondary cell wall,eventually leading to the death of the protoplast.
Therefore,the deposition begins from the primary wall and moves towards the secondary wall.

(A) Tracheids are elongated,tube-like cells with tapering ends that lack open pores; their end walls possess pits for the lateral movement of water.
In contrast,vessels are long,cylindrical,tube-like structures formed by a row of cells placed end-to-end. The end walls of these vessel elements are dissolved or perforated to form a continuous channel for efficient water conduction.
Therefore,the end walls of tracheids are pitted,and the end walls of vessels are perforated.

(B) Fibre tracheids are elongated cells that possess features intermediate between tracheids and libriform fibres.
They are derived from tracheids and exhibit a reduced number of bordered pits compared to typical tracheids.
These cells provide mechanical support and are found in the xylem of many angiosperms.

(C) The correct answer is $C$.
Libriform fibres are thick-walled wood fibres that are characterized by the presence of simple pits.
These fibres are typically longer and have thicker walls compared to fibre tracheids,which possess bordered pits.

(B) Xylem fibres are also known as wood fibres.
These are sclerenchymatous cells associated with the xylem.
They provide mechanical support to the plant and are characterized by the presence of bordered pits.

(B) The term 'Leptome' was coined by Haberlandt in $1914$. It refers to the soft-walled conducting part of the phloem,which is known as the sieve element. Therefore,'Leptome' is a synonym for sieve elements.

(D) Companion cells are specialized parenchyma cells that are closely associated with sieve tube elements in the phloem of angiosperms.
They are absent in pteridophytes and gymnosperms.
In gymnosperms,albuminous cells perform a similar function to companion cells.
Therefore,companion cells are exclusively found in angiosperms.

(D) The correct answer is $D$.
$1$. Sieve tube elements are specialized cells of the phloem that lose their nucleus at maturity to facilitate the transport of food.
$2$. Vessels are long,tube-like structures in the xylem that lose their protoplasm and nucleus upon maturation to allow efficient water conduction.
$3$. Tracheids are elongated cells in the xylem that also become dead and lose their nucleus at maturity.
Therefore,all the mentioned cells lack a nucleus in their mature state.

(D) Lignin is a complex polymer that provides structural support and rigidity to plant cell walls.
Sieve tubes,albuminous cells,and phloem parenchyma are all components of the phloem tissue.
Phloem tissue is primarily composed of living cells (sieve elements,companion cells,and parenchyma) which typically have thin,cellulosic cell walls.
Since none of the options listed contain lignified walls,the correct answer is $D$.

(B) Bast fibres,also known as phloem fibres,are made of sclerenchymatous cells.
These fibres are generally absent in primary phloem but are commonly found in secondary phloem.
They provide mechanical support to the plant body.
Therefore,the correct option is $B$.

(C) In the autumn season, the activity of the cambium is reduced, and the sieve tubes become inactive.
During this period, a carbohydrate substance known as $Callose$ is deposited on the $Sieve plates$ of the sieve tubes.
This deposition forms a layer called the callus pad, which blocks the pores of the sieve plates, thereby preventing the transport of food materials.

(A) The cortex is primarily composed of parenchyma cells,which are thin-walled and living cells responsible for storage and support.
However,when fibres are present in the cortex,they are specialized cells known as sclerenchyma fibres.
Sclerenchyma fibres provide mechanical strength and support to the plant body.
Therefore,the fibres found in the cortex are of sclerenchymatous origin.

(B) $Aerenchyma$ is a specialized type of $Parenchyma$ tissue that contains large air cavities or air spaces.
These air spaces help in the exchange of gases and provide buoyancy to aquatic plants (hydrophytes),allowing them to float on the water surface.
Therefore,the correct answer is $Parenchyma$.

(A) Collenchyma cells are living mechanical tissues that provide tensile strength and flexibility to young stems and petioles.
Sclerenchyma and Sclereids are dead cells at maturity that provide mechanical support.
Phloem is primarily involved in the translocation of food.
Therefore,the living cells that provide tensile and mechanical strength are Collenchyma cells.

(D) $Xylem$ is a complex permanent tissue in plants responsible for the conduction of water and minerals.
It consists of four main types of elements:
$1$. $Tracheids$
$2$. $Vessels$
$3$. $Xylem$ $parenchyma$
$4$. $Xylem$ $fibers$
Among the given options,$Tracheid$ is a fundamental component of $Xylem$,whereas $Sieve$ $tube$ is a component of $Phloem$,$Medullary$ $ray$ is a radial system of parenchyma,and $Sclereid$ is a type of sclerenchyma cell.

(B) Sclerenchyma cells are characterized by being dead at maturity,having thick,lignified secondary cell walls,and providing structural support to the plant.
Specifically,sclerenchyma fibers are long,narrow,and pointed at both ends.
In contrast,sclereids are typically shorter and irregular in shape,while parenchyma and collenchyma cells are living and generally lack heavy lignification.

(A) Plant fibres are structural elements that provide mechanical support to the plant body.
These fibres are primarily derived from sclerenchymatous tissues.
Specifically,they are found in the $Xylem$ (xylem fibres),$Phloem$ (phloem or bast fibres),and as independent $Sclerenchyma$ bundles (pericyclic fibres).
Therefore,the correct source of plant fibres is $Xylem$,$Phloem$,and $Sclerenchyma$.

(C) In angiosperms,the phloem consists of sieve tube elements,companion cells,phloem parenchyma,and phloem fibres.
In gymnosperms,the phloem consists of sieve cells,phloem parenchyma,and phloem fibres.
Gymnosperms lack both sieve tubes and companion cells.
Among the given options,the most significant functional and structural difference that distinguishes the phloem of angiosperms from gymnosperms is the presence of companion cells in angiosperms,which are absent in gymnosperms.

(A) Vessels are long, cylindrical tube-like structures made up of many cells called vessel members, each with lignified walls and a large central cavity.
In $99\%$ of angiosperms, vessels are the characteristic feature of the xylem.
In contrast, gymnosperms generally lack vessels in their xylem, with the exception of the order Gnetales (e.g., Gnetum, Ephedra, and Welwitschia).
Therefore, vessels are primarily and characteristically found in the xylem of angiosperms.

(B) Porous wood is a characteristic feature of angiosperms (hardwood).
It is called 'porous' because it contains a large number of vessels,which appear as pores in the cross-section of the wood.
Therefore,the correct answer is $B$ (Vessels).

(A) Tracheids and vessels are the primary conducting elements of the $Xylem$ tissue.
$Xylem$ is a complex permanent tissue responsible for the conduction of water and minerals from roots to the stem and leaves.
Tracheids are elongated,tube-like cells with thick,lignified walls and tapering ends.
Vessels are long,cylindrical tube-like structures made up of many cells called vessel members,each with lignified walls and a large central cavity.
Since both are integral components of $Xylem$,the correct option is $A$.

(C) Commercial jute fibres are obtained from phloem fibres. These are sclerenchymatous fibres,but because of their presence in the phloem,they are called phloem fibres. They are primarily used in the manufacturing of ropes,bags,and carpets.

(B) is the correct answer.
$Vessels$ are long, cylindrical tube-like structures made up of many cells called vessel members.
Each vessel member has lignified walls and a large central cavity.
The end walls of these vessel members are perforated, which allows for the efficient transport of water and minerals throughout the plant body.
These perforations can be simple or multiple, facilitating the continuity of the water column.

(B) Companion cells are specialized parenchymatous cells that are closely associated with sieve tube elements in the phloem of angiosperms.
They maintain the pressure gradient in the sieve tubes and are essential for the translocation of food materials.
Therefore,companion cells are a component of the phloem tissue.

(C) Companion cells are specialized parenchyma cells that are closely associated with sieve tube elements in the phloem of angiosperms.
They are connected to sieve tube elements through plasmodesmata.
Companion cells maintain the pressure gradient in the sieve tubes and assist in the loading and unloading of sugars (sucrose) into the sieve elements.

(B) Sieve tubes are specialized cells in the phloem tissue responsible for the transport of food. When these tubes are damaged,they are sealed by the deposition of a polysaccharide called $Callose$. This substance forms a $Callus$ pad over the sieve pores to prevent the leakage of sap and to isolate the damaged area.

(B) Vessels are long,cylindrical,tube-like structures made up of many cells called vessel members,each with lignified walls and a large central cavity.
They are devoid of protoplasm.
Vessel members are interconnected through perforations in their common walls.
The primary function of vessels is the conduction of water and minerals from the roots to the stem and leaves in angiosperms.

(C) . Sieve tube elements are specialized cells in the phloem that are responsible for the translocation of food. During their maturation,they lose their nuclei and other organelles to facilitate the flow of sap,but they retain a thin layer of cytoplasm along the cell wall.