Meristematic Tissue Questions in English

(A) . The statement is correct. $F$.$A$.$L$. Clowes proposed the Quiescent Center theory,describing the root apex as having an inverted cup-shaped region of inactive cells.
$B$. The statement is correct. The waiting meristem (quiescent center) is characterized by low metabolic activity,resulting in low concentrations of $RNA$,$DNA$,and proteins compared to surrounding meristematic tissues.
$C$. The statement is correct. The cells of the reserve meristem (quiescent center) remain inactive under normal conditions but resume division to replace damaged cells if the root apex is injured.
Therefore,all statements are correct.

(C) The Assertion is correct because intercalary meristems are found between permanent tissues,typically at the base of leaves,above the nodes,or below the nodes.
The Reason is incorrect because meristematic cells,including those of the intercalary meristem,are characterized by having small or no vacuoles,dense cytoplasm,and a prominent nucleus to facilitate rapid cell division.
Large vacuoles are typically found in mature cells undergoing the elongation phase.

(C) Higher plants possess specific areas that actively divide to form new cells. These areas are known as meristems.
Meristems are classified into three types based on their location:
$(i)$ Apical meristem: Located at the tips of roots and shoots.
$(ii)$ Intercalary meristem: Located between permanent tissues.
$(iii)$ Lateral meristem: Responsible for secondary growth in thickness.

(D) The cells in the root and shoot apex exhibit the following characteristics:
$(i)$ They are rich in protoplasm.
$(ii)$ They possess conspicuous nuclei.
$(iii)$ Their cell walls are primary in nature,thin,and cellulosic,with abundant plasmodesmatal connections.
Therefore,all the given options are correct.

(A) Meristematic cells are characterized by their ability to divide continuously throughout the life of the plant.
This process of continuous division allows them to maintain their population and contribute to the growth of the plant,a property known as self-perpetuation.
Unlike mature cells,meristematic cells remain in a state of active division.

(C) Lateral meristems are responsible for secondary growth in plants,which increases the girth or diameter of the stem and root.
These meristems are cylindrical in nature.
The primary examples of lateral meristems are the vascular cambium and the cork cambium (also known as phellogen).
Vascular cambium is responsible for the production of secondary xylem and secondary phloem.
Cork cambium is responsible for the production of periderm (cork or phellem on the outside and phelloderm on the inside).

(A) Stem cells are undifferentiated cells that have the unique ability to differentiate into various specialized cell types. Depending on their potency,such as totipotency,they can give rise to any type of cell in the organism. While they are present in both plants and animals,they are particularly abundant in plant meristematic tissues.

(N/A) The increase in length of plant organs over time is due to the activity of apical meristems located at their tips. This type of growth is known as primary growth.

(C) The root tip is divided into three zones: the region of meristematic activity,the region of elongation,and the region of maturation.
$1$. The region of meristematic activity is located a few millimeters above the root cap.
$2$. The cells in this region are very small,thin-walled,and with dense protoplasm.
$3$. These cells divide repeatedly,meaning they are undifferentiated and actively undergoing mitosis to produce new cells for the root.

(D) Meristematic tissues consist of cells that are actively dividing $(C)$.
These cells are undifferentiated $(B)$,meaning they have not yet acquired a specific structure or function and retain the capacity to divide.
Therefore,both $B$ and $C$ are correct characteristics of meristematic cells.

(B) The cells that have the capacity to divide actively are known as meristematic cells. $A$ group of such actively dividing cells is collectively referred to as $Meristematic$ tissue. These tissues are responsible for the growth of the plant body.

(B) The apical meristem is located at the shoot apex. During the formation of leaves and the elongation of the stem,some cells are left behind from the shoot apical meristem. These cells constitute the axillary bud. Axillary buds are present in the axils of leaves and are capable of forming a branch or a flower.

(A) $1$. Apical meristems are found at the shoot and root apices and are responsible for primary growth,which increases the length of the plant axis.
$2$. Lateral meristems (such as vascular cambium and cork cambium) are found in the mature regions of roots and shoots and are responsible for secondary growth,which increases the girth or thickness of the plant organ.
$3$. Therefore,$P$ corresponds to the Apical meristem and $Q$ corresponds to the Lateral meristem.

(A) The meristematic tissue that occurs between mature tissues is called the intercalary meristem.
It is a portion of the primary meristem that gets separated from the apical meristem during the development of the plant body.
It is commonly found in grasses and helps in the regeneration of parts removed by grazing herbivores.

(D) In the longitudinal section of a shoot apex,the region labeled $P$ represents the shoot apical meristem,which is a region of actively dividing meristematic cells responsible for primary growth. The structure labeled $Q$ represents an axillary bud,which develops in the axil of a leaf and is capable of forming a branch or a flower. Therefore,the correct identification is $P$ as the meristematic region and $Q$ as the axillary bud,which corresponds to option $D$.

(B) Meristematic tissues are characterized by their ability to undergo continuous cell division. They are undifferentiated cells that eventually lose the ability to divide and become differentiated to form permanent tissues. Therefore,the statement that 'Meristematic tissue is differentiated' is incorrect,as differentiated cells constitute permanent tissue,not meristematic tissue. Fascicular cambium,interfascicular cambium,and cork cambium are indeed examples of secondary meristems that arise from permanent tissues.

(A) In dicot stems, the vascular bundles contain a strip of meristematic tissue between the primary xylem and primary phloem, which is known as the $Intrafascicular \text{ } cambium$.
This tissue is responsible for secondary growth in plants.
Later, cells of medullary rays adjoining the $Intrafascicular \text{ } cambium$ become meristematic and form the $Interfascicular \text{ } cambium$.
Together, these form a complete $Cambial \text{ } ring$.
Since the question specifically asks for the tissue present between primary phloem and primary xylem, the correct answer is $Intrafascicular \text{ } cambium$.

(C) The correct answer is $C$.
$1$. Cork cambium,vascular cambium,and lateral meristem are all types of lateral meristems responsible for secondary growth in plants.
$2$. Intercalary meristem is a type of primary meristem,which is responsible for the increase in the length of the plant (primary growth),typically found at the base of leaves or internodes.
$3$. Therefore,intercalary meristem is the odd one out as it is not involved in secondary growth.

(A) Apical and lateral meristems are responsible for the growth of the plant body in length and girth,respectively.
These tissues consist of actively dividing cells that contribute to the vegetative growth of the plant.
In somatic cells of plants,the type of cell division that occurs to maintain the same chromosome number in daughter cells is mitosis.
Therefore,mitosis is the type of cell division observed in apical and lateral meristems.

(D) Plants possess the capacity for unlimited growth throughout their life. This phenomenon is due to the presence of meristematic tissue at certain locations in their body.
Meristematic tissues consist of actively dividing cells that continuously add new cells to the plant body,leading to indeterminate growth.
Parenchyma,collenchyma,and sclerenchyma are permanent tissues that have lost the ability to divide.

(B) In the provided diagram,$P$ represents the Shoot Apical Meristem,which is responsible for the primary growth of the shoot.
$Q$ represents the Fascicular Cambium,which is a lateral meristem responsible for secondary growth in plants.

(B) Meristematic tissue consists of actively dividing cells that are responsible for the growth of the plant.
These cells are undifferentiated and have the ability to undergo mitosis continuously to produce new cells.
In contrast,Parenchyma,Collenchyma,and Sclerenchyma are permanent tissues that have lost the ability to divide.

(D) The meristematic region consists of cells that are actively dividing.
$I-$ Correct: Meristematic cells are characterized by their ability to divide continuously.
$II-$ Correct: These cells are metabolically active and rich in protoplasm.
$III-$ Correct: They contain a large,conspicuous nucleus to support high metabolic activity.
$IV-$ Incorrect: Meristematic cells are undifferentiated (or immature) cells,not differentiated.
$V-$ Correct: The cell walls are primary,thin,and cellulosic,and they possess abundant plasmodesmata to facilitate communication between cells.
Therefore,the correct characteristics are $I, II, III,$ and $V$.