Permanent Tissue Questions in English

(C) The pulp of fruits is primarily composed of $Parenchyma$ cells. $Parenchyma$ is a type of simple permanent tissue that serves as the main packing tissue in plants. It is responsible for storage of food,photosynthesis,and secretion. In fruits,these cells are often thin-walled and store nutrients,sugars,and water,which gives the fruit its fleshy texture.

(C) Plant tissues are broadly classified into meristematic and permanent tissues.
Meristematic tissues,such as $Apical$ $meristem$ and $Cambium$,consist of actively dividing cells that are undifferentiated.
Parenchyma is a type of simple permanent tissue.
Permanent tissues are composed of cells that have lost the ability to divide and have become structurally and functionally differentiated to perform specific roles in the plant body.
Therefore,$Parenchyma$ is the correct answer as it is a differentiated permanent tissue.

(B) Safranin is a biological stain used in histology and cytology. It is a basic dye that has a high affinity for lignified cell walls. Therefore,it is commonly used to stain xylem tissues and other lignified structures in plant anatomy,appearing bright red under a microscope.

(B) Mature sieve tube elements are living cells that lack a nucleus at maturity,but they retain a peripheral layer of cytoplasm. In contrast,xylem vessels are dead cells at maturity that possess thick,lignified secondary cell walls and lack both a nucleus and cytoplasm. The most significant structural difference between them is that sieve tubes lack lignified walls,whereas xylem vessels possess them.

(D) Sieve tube elements are the main conducting cells of the phloem in angiosperms.
At maturity,these cells lose their nucleus and other organelles like ribosomes and vacuoles to facilitate the efficient transport of food (sucrose).
However,they remain alive and maintain their metabolic functions through the help of adjacent companion cells,which possess a nucleus and are connected to the sieve tube elements via plasmodesmata.

(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.
$1$. Vessels possess perforation plates at their ends,which allow for the continuous flow of water,whereas tracheids do not have such plates.
$2$. Both vessels and tracheids are dead at maturity and lack a nucleus.
$3$. Therefore,the primary structural difference that distinguishes vessels from tracheids is the presence of perforation plates at their ends.

(B) Sieve tubes are components of the phloem tissue,which are living cells at maturity,although they lack a nucleus. Tracheids are components of the xylem tissue,which are dead cells at maturity due to heavy lignification of their cell walls. The primary difference between them is that sieve tubes are living cells with thin cellulose walls,whereas tracheids are dead cells with thick,lignified walls. Therefore,the lack of heavy lignin deposition in sieve tubes distinguishes them from tracheids.

(B) The correct answer is $B$.
$1$. $Parenchyma$ is a living tissue that provides support through turgor pressure but is not primarily a mechanical tissue.
$2$. $Collenchyma$ is a living mechanical tissue characterized by uneven thickening of cell walls due to the deposition of cellulose,hemicellulose,and pectin. It lacks $Lignin$ deposition,making it non-lignified.
$3$. $Sclerenchyma$ is a dead mechanical tissue that is heavily lignified.
$4$. $Chlorenchyma$ is a type of parenchyma containing chloroplasts,primarily involved in photosynthesis rather than mechanical support.

(A) 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. It is typically found in the hypodermis of dicotyledonous stems and is characteristic of herbaceous plants,including herbaceous climbers,as it provides flexibility and tensile strength without restricting growth.

(A) Sclerenchyma is a type of permanent tissue that provides mechanical strength to plants. In conditions of water scarcity (xerophytic conditions),plants often develop more sclerenchyma to prevent wilting and provide structural support to the plant body. Sclerenchyma cells have thick,lignified secondary walls that help the plant survive in dry environments.

(C) Bordered pits are specialized structures found in the cell walls of tracheids and vessel elements in the xylem of plants.
Among the given options,metaxylem (the later-formed primary xylem) contains vessels and tracheids that possess bordered pits to facilitate the lateral transport of water.
Protoxylem typically has annular or spiral thickenings and lacks fully developed bordered pits.
Therefore,the correct answer is $C$ (Metaxylem).

(A) Collenchyma is a simple permanent tissue that provides mechanical support to young stems and petioles.
There are three main types of collenchyma based on the pattern of cell wall thickening:
$1$. Angular collenchyma: Thickening occurs at the corners (e.g.,$Helianthus$ stem).
$2$. Lamellar collenchyma: Thickening occurs in tangential walls (e.g.,$Raphanus$ stem).
$3$. Lacunar collenchyma: Thickening occurs on the walls bordering the intercellular spaces (e.g.,$Cucurbita$ stem).
Therefore,lacunar collenchyma is characteristic of the hypodermis of $Cucurbita$ stems.

(D) Companion cells are specialized parenchyma cells that are closely associated with the sieve tube elements in the phloem of angiosperms.
They are connected to the sieve tube elements through pit fields present between their common longitudinal walls.
These cells help in maintaining the pressure gradient in the sieve tubes and are essential for the translocation of food materials.
Therefore,the correct option is $D$.

(A) Parenchyma cells are simple permanent tissues that perform various functions like storage,photosynthesis,and secretion.
Some parenchyma cells are specialized to store waste or excretory products such as tannins,resins,oils,or crystals (like calcium oxalate).
These specialized parenchyma cells are known as $Idioblasts$.

(A) The xylem is a complex permanent tissue in plants responsible for the conduction of water and dissolved minerals from the roots to the stem and leaves. This mixture of water and minerals is often referred to as sap. Therefore,the primary function of xylem is the conduction of sap.

(C) Xylem tissue is a complex permanent tissue that conducts water and minerals.
It consists of four types of elements: xylem tracheids,xylem vessels,xylem parenchyma,and xylem fibers.
Among these,xylem tracheids,xylem vessels,and xylem fibers are dead cells at maturity because they lack protoplasm.
Xylem parenchyma is the only living component of the xylem tissue,which helps in the storage of food materials like starch or fat and in the radial conduction of water.

(B) The mechanical tissues in plants provide structural support.
$1$. $Parenchyma$ $(D)$ is a simple permanent tissue consisting of living cells,but it is primarily involved in storage and photosynthesis,not mechanical support.
$2$. $Sclerenchyma$ $(A)$ provides mechanical strength but consists of dead cells at maturity.
$3$. $Collenchyma$ $(B)$ is a simple permanent tissue composed of living cells that provides mechanical support to the growing parts of the plant,such as young stems and petioles of leaves.
Therefore,$Collenchyma$ is the correct answer as it is a living mechanical tissue.

(C) Companion cells are specialized parenchymatous cells that are closely associated with sieve tube elements in the phloem of angiosperms.
They are connected to the sieve tube elements by pit fields present between their common longitudinal walls.
Companion cells maintain the pressure gradient in the sieve tubes and help in the translocation of food materials.

(B) Collenchyma is a living mechanical tissue that provides structural support to the growing parts of the plant,such as the petiole of a leaf and young stems.
It consists of cells that are thickened at the corners due to the deposition of cellulose,hemicellulose,and pectin.
Unlike sclerenchyma,which provides support to mature parts,collenchyma allows for the elongation and growth of young plant organs.

(B) The leaves of $Victoria \text{ } regia$ (a giant water lily) are known for their immense size and rigidity.
This structural support is provided by the presence of $stellate \text{ } sclereids$ (also known as $astrosclereids$) within the leaf tissue.
These star-shaped cells act as a mechanical framework, providing strength and preventing the large leaves from collapsing or tearing under their own weight or water currents.

(A) Aerenchyma is a specialized type of parenchyma tissue characterized by large air-filled cavities or intercellular spaces.
In aquatic plants (hydrophytes),these air spaces help in the exchange of gases and provide buoyancy,allowing the plants to float on the water surface.
Therefore,the primary function of aerenchyma is to provide buoyancy to aquatic plants.

(C) In angiosperms,the sieve tube elements are arranged longitudinally. The end walls of these cells are perforated in a sieve-like manner to form the sieve plates. These sieve plates are typically oblique and located on the end walls of the sieve tube elements,facilitating the transport of food materials.

(A) Sclerenchyma is a type of permanent tissue in plants that provides mechanical support. It consists of two types of cells: fibers and sclereids.
$1$. Fibers are long,narrow,and pointed cells that usually occur in bundles.
$2$. Sclereids are spherical,oval,or cylindrical,highly thickened,dead cells with very narrow cavities (lumens).
Therefore,the long,pointed sclerenchymatous cells are known as fibers.

(D) The phloem tissue in angiosperms consists of sieve tube elements,companion cells,phloem parenchyma,and phloem fibers.
$1$. Sieve tube elements are living but lack a nucleus at maturity.
$2$. Companion cells are specialized parenchyma cells that are closely associated with sieve tube elements.
$3$. Companion cells contain a dense cytoplasm and a prominent,functional nucleus,which controls the activities of the sieve tube elements.
$4$. Tracheids and vessels are components of xylem,not phloem.
Therefore,the companion cell is the correct answer.

(C) Fibers are a type of sclerenchyma cells.
Sclerenchyma is a simple permanent tissue that provides mechanical support to the plant.
Fibers are elongated,narrow,thick-walled,and lignified cells that are often found in bundles.
They are considered the longest plant cells and provide structural strength to various plant parts.

(D) Phloem tissue is composed of sieve tube elements,companion cells,phloem parenchyma,and phloem fibers.
Phloem fibers (also known as bast fibers) are made up of sclerenchymatous cells.
These are generally absent in primary phloem but are found in secondary phloem.
They provide mechanical support to the plant body.

(B) Vessels are a characteristic feature of angiosperms.
They are present in almost all angiosperms.
Among gymnosperms,they are generally absent,except in the order Gnetales (e.g.,Gnetum,Ephedra,and Welwitschia),where they are present.
Therefore,vessels are found in most angiosperms and a few gymnosperms.

(B) Collenchyma is a simple permanent tissue found in the hypodermis of dicot stems and leaves.
It consists of cells that are thickened at the corners due to the deposition of cellulose,hemicellulose,and pectin.
This tissue provides mechanical support to the growing parts of the plant,such as young stems and petioles of leaves,allowing them to bend without breaking.
Therefore,it provides both tensile strength and flexibility.

(A) $P-protein$ (Phloem protein) is a characteristic protein found in the sieve elements of the phloem in angiosperms.
It is involved in the repair of sieve plate pores and the sealing of damaged sieve tubes to prevent the loss of phloem sap.
Therefore,it is a component of the sieve tube.

(D) Simple permanent tissues are composed of only one type of cells which perform a similar function.
In plants,simple permanent tissues are classified into three main types: Parenchyma,Collenchyma,and Sclerenchyma.
Since all three options listed are examples of simple permanent tissues,the correct answer is $D$.

(A) Collenchyma cells are living at maturity and retain their protoplasm,which allows them to provide flexibility and mechanical support to growing parts of the plant.
In contrast,sclerenchyma cells are dead at maturity and lack protoplasm,possessing thick,lignified secondary walls that provide structural rigidity and strength.
Therefore,the retention of protoplasm at maturity is the key difference between these two tissues.

(B) Collenchyma is a type of simple permanent tissue found in plants.
Its cells are characterized by uneven thickenings of their cell walls.
These thickenings are primarily composed of cellulose,hemicellulose,and pectin.
Among these,pectin is deposited in large amounts at the corners of the cells,providing structural support and flexibility to the growing parts of the plant.

(D) Callose is a polysaccharide that is deposited in the sieve plates of sieve tube elements. During the dormant season,such as winter or autumn,the plant deposits callose to block the sieve pores,effectively sealing off the sieve tubes to prevent the loss of nutrients and to protect the plant during unfavorable conditions. This process is known as the formation of a 'callose plug'.

(A) The $Parenchyma$ tissue is composed of cells that are generally isodiametric and have thin cell walls made of cellulose.
In contrast,$Collenchyma$ cells have uneven thickenings of cellulose,hemicellulose,and pectin at the corners.
$Fibers$ and $Sclereids$ are types of $Sclerenchyma$ tissue,which possess highly thickened,lignified cell walls that provide mechanical support to the plant.

(B) Collenchyma is a type of simple permanent tissue found in plants.
It is characterized by the uneven thickening of its cell walls.
These thickenings are primarily composed of cellulose,hemicellulose,and pectin.
Suberin is found in cork cells,and lignin is the characteristic thickening found in sclerenchyma cells.
Therefore,the correct answer is pectin.

(A) Lignin is a complex organic polymer that is deposited in the cell walls of many plants,making them rigid and woody.
It is a characteristic feature of the secondary cell walls of xylem vessels and tracheids,which are responsible for the conduction of water and minerals.
Therefore,lignin is the main component of the cell wall of xylem tissue.

(D) Collenchyma is a mechanical tissue that provides structural support to young,growing parts of plants.
It is typically found in the hypodermis of dicot stems and the petioles of leaves.
However,collenchyma is characteristically absent in the roots of all plants and in the stems of monocotyledonous plants.
Since both roots and monocot stems lack collenchyma,the correct answer is $D$ (All of the above).

(D) Parenchyma is a simple permanent tissue that forms the major component within organs.
$1$. The cells of parenchyma are generally isodiametric,meaning they have equal diameters in all directions.
$2$. Their cell walls are thin and made of cellulose,and they often possess intercellular spaces between them.
$3$. They are metabolically active and perform diverse functions such as photosynthesis (chlorenchyma),storage of food,and secretion.

(A) The $Parenchyma$ tissue is the most common and fundamental simple permanent tissue in plants.
It consists of relatively unspecialized cells with thin cell walls made of cellulose.
These cells are generally isodiametric and possess intercellular spaces.
$Parenchyma$ performs various functions such as photosynthesis, storage of food materials (like starch, proteins, and oils), and secretion.
Due to its thin-walled nature and metabolic activity, it serves as the primary tissue for the storage of food in roots, stems, and leaves.

(D) Sieve tubes are long,tube-like structures arranged longitudinally and are associated with companion cells.
Their end walls are perforated in a sieve-like manner to form 'sieve plates'.
These structures are specialized for the translocation of food materials in plants.
Therefore,the presence of porous end walls (sieve plates) is a characteristic feature of sieve tubes.

(D) Sieve tubes are the main conducting elements of the phloem in angiosperms.
They are long,tube-like structures arranged longitudinally and are associated with companion cells.
They possess a wide lumen to facilitate the bulk flow of food materials (translocation of nutrients).
Furthermore,they contain very little peripheral cytoplasm and lack a nucleus at maturity,which minimizes resistance to the flow of sap.

(C) Vessels and tracheids are both types of xylem elements involved in water conduction.
$1$. Vessels are long,tube-like structures formed by a row of cells placed end-to-end.
$2$. The end walls of vessels are perforated,which allows for the free flow of water between adjacent vessel elements.
$3$. In contrast,tracheids are elongated cells with tapering ends and do not have such perforations in their end walls.
$4$. Therefore,the presence of perforated end walls (or openings) is a key feature that distinguishes vessels from tracheids.

(C) $Sclerenchyma$ cells are dead at maturity and lack protoplasm. They provide mechanical support to the plant body. In contrast, $Parenchyma$ and $Collenchyma$ are living tissues that contain protoplasm at maturity.

(C) Sieve tubes are the main conducting elements of phloem in angiosperms.
They lack a nucleus at maturity and are dependent on companion cells for their metabolic activities.
Companion cells are specialized parenchyma cells that are closely associated with sieve tube elements via plasmodesmata.
They maintain the pressure gradient in the sieve tubes and regulate the loading and unloading of sugars.

(A) In plants,the phloem is responsible for the translocation of food (sugars).
In angiosperms,the phloem consists of sieve tube elements,companion cells,phloem parenchyma,and phloem fibers.
However,in gymnosperms and pteridophytes,sieve tubes and companion cells are absent.
Instead,they possess sieve cells,which are the primary sugar-conducting components.
Therefore,the correct answer is $A$.

(C) The phloem tissue consists of four main components: sieve tube elements,companion cells,phloem parenchyma,and phloem fibers.
Sieve tube elements are the conducting cells of the phloem.
At maturity,sieve tube elements lose their nucleus and other organelles like ribosomes and vacuoles to facilitate the efficient transport of food materials (sucrose).
Therefore,the sieve tube element is the component that lacks a nucleus at maturity.

(B) $Phellem$ (cork) is composed of dead cells that are compactly arranged and rectangular in shape. These cells have suberized cell walls,which make them impermeable to water and gases.

(B) : Tracheids are elongated,dead cells with hard lignified walls,wide lumens,and narrow walls with spiral,annular,reticulate,scalariform,and pitted thickening,but they lack perforated end walls or septa.
This means they have intact end walls,unlike vessels.
Vessels are long,cylindrical,tube-like structures made of many cells called vessel members,each with lignified walls and a large central cavity.
Vessel members are interconnected through perforations in their common walls,making them perforated,whereas tracheids are imperforate.

(A) $(A) :$ Companion cells are specialized parenchyma cells found in the phloem of angiosperms.
Each companion cell is closely associated with a sieve tube element.
They are connected to the sieve tube elements through numerous plasmodesmata.
Companion cells play a crucial role in the loading of sugars into the sieve tube elements via active transport,which is essential for the translocation of food.

(C) : The protoxylem differentiates in the parts of the primary body that have not completed their growth and differentiation.
In the shoot, the protoxylem matures among actively elongating tissues and is, therefore, subjected to stresses.
In the root, the protoxylem elements persist longer because they mature beyond the region of maximum growth.
During this process of differentiation, annular and spiral thickenings take place in the conducting elements to provide structural support while allowing for further growth.