Tissue Culture Questions in English

(N/A) It is scientifically possible. With the help of tissue culture, it is possible to achieve the propagation of several plants in a very short duration. This method of producing thousands of plants through tissue culture is called micropropagation. Each of these plants is genetically identical to the original plant from which they were grown. They are also called somaclones.

(N/A) Plants raised through tissue culture are clones of the parent plant,meaning they are genetically identical to the original plant.
The utility of these plants includes:
$1$. Maintaining desirable traits: Since they are clones,they retain all the beneficial characteristics of the parent plant.
$2$. Rapid multiplication: Tissue culture allows for the production of a large number of plants in a very short period.
$3$. Disease-free plants: It is possible to produce virus-free plants from infected parents by using meristem culture.
$4$. Conservation: It helps in the conservation of rare or endangered plant species.

(N/A) The primary physical barrier in a plant cell during protoplast fusion experiments is the rigid cell wall.
To overcome this barrier,the plant tissue is treated with specific cell wall-degrading enzymes,primarily cellulase and pectinase.
These enzymes digest the cellulose and pectin components of the cell wall,respectively,thereby releasing the naked protoplast,which is bounded only by the plasma membrane.

(N/A) The advantages of tissue culture methods are:
$(i)$ By application of these methods,it is possible to achieve propagation of a large number of plants in very short durations.
$(ii)$ This method of producing thousands of plants through tissue culture is called micro-propagation.
$(iii)$ Each of these plants will be genetically identical to the original plant from which they were grown,i.e.,they are somaclones.
$(iv)$ Many important food plants like tomato,banana,apple,etc.,have been produced on a commercial scale using this method.
$(v)$ Another important application of the method is the recovery of healthy plants from diseased plants. Although the plant is infected with a virus,the meristem (apical and axillary) is free of virus. Hence,one can remove the meristem and grow it in-vitro to obtain virus-free plants. Scientists have succeeded in culturing meristems of banana,sugarcane,potato,etc.

(N/A) The capacity to generate a whole plant from any cell/explant is called totipotency.
By application of these methods,it is possible to achieve propagation of many plants in very short durations.
This method of producing thousands of plants through tissue culture is called micropropagation.
Each of these plants will be genetically identical to the original plant from which they were grown,i.e.,they are somaclones.
Many important food plants like tomato,banana,apple,etc.,have been produced on a commercial scale using this method.
Another important application of the method is the recovery of healthy plants from diseased plants.
Although the plant is infected with a virus,the meristem (apical and axillary) is free of virus.
Hence,one can remove the meristem and grow it in vitro to obtain virus-free plants.
Scientists have succeeded in culturing meristems of banana,sugarcane,potato,etc.

(N/A) $Somatic$ $hybridisation$: Isolated protoplasts from two different varieties of plants,each having a desirable character,can be fused to obtain hybrid protoplasts. These can be further grown to form a new plant. These hybrids are called $somatic$ $hybrids$,and the process is known as $somatic$ $hybridisation$.
$Totipotency$: The capacity of any cell or explant to generate a whole plant when grown in a test tube under sterile conditions in special nutrient media is called $totipotency$.

(A) In plant tissue culture,sucrose is the most commonly used carbon source. Sucrose is a disaccharide consisting of glucose and fructose. It is preferred because it is relatively inexpensive,easily sterilized,and readily metabolized by plant cells in culture media.

(B) Even if a plant is infected with a virus,the meristem (apical and axillary) is free of the virus. Therefore,one can remove the meristem and grow it in vitro to obtain virus-free plants. This technique is known as $Meristem$ $Culture$,which is a type of $Tissue$ $Culture$.

(B) The capacity of a plant cell to regenerate into a whole plant is known as $Totipotency$. This is a fundamental principle of plant tissue culture,where any living plant cell (explant) can be cultured to produce a complete,genetically identical plant under suitable laboratory conditions.

(C) Pomato is a somatic hybrid plant produced through the technique of somatic hybridization.
It is created by the fusion of protoplasts from two different plant species: Tomato $(Solanum \text{ } lycopersicum)$ and Potato $(Solanum \text{ } tuberosum)$.
Although it was developed to combine the traits of both plants, it did not become commercially successful as it did not produce both high-quality tomatoes and potatoes simultaneously.

(A) Somaclones are genetically identical plants produced through tissue culture techniques.
Micropropagation is a method of tissue culture that allows for the production of a large number of genetically identical plantlets from a single explant.
Since these plantlets are derived from the same parent tissue via asexual reproduction (mitosis),they are referred to as somaclones.

(B) plant cell consists of a cell wall and a protoplast (the living content of the cell).
When the cell wall is removed by enzymatic digestion (using enzymes like cellulase and pectinase),the remaining living part of the cell,which is bounded by the plasma membrane,is known as a $Protoplast$.
$Protoplasts$ are widely used in plant tissue culture and somatic hybridization experiments.

(D) In plant tissue culture,the nutrient medium provides essential nutrients for the growth and development of explants.
Sucrose is the most commonly used carbon source in these media because it is easily metabolized by plant cells,is relatively inexpensive,and remains stable during the autoclaving process.
Other sugars like glucose or fructose are sometimes used,but sucrose is preferred for its efficiency and cost-effectiveness.

(C) Micropropagation is a method of plant propagation that involves the production of a large number of plants in a short duration using tissue culture techniques.
In this process,the plantlets produced are genetically identical to the original plant from which they were grown,and are therefore referred to as somaclones.
Thus,micropropagation is essentially a form of tissue culture.

(C) somatic hybrid is a plant produced by the fusion of protoplasts from two different plant species.
Pomato is a classic example of a somatic hybrid,created by the fusion of protoplasts from potato $(Solanum \, tuberosum)$ and tomato $(Solanum \, lycopersicum)$.
$Atlas \, 66$ is a wheat variety rich in protein.
$A. \, esculentus$ (Okra) is a vegetable crop.
$Himgiri$ is a variety of wheat resistant to hill bunt and leaf rust.

(A) To obtain plant protoplasts,the plant cell wall must be degraded. The plant cell wall is primarily composed of cellulose,hemicellulose,and pectin. Cellulase is the enzyme that breaks down cellulose,which is the main structural component of the plant cell wall. Therefore,cellulase (often in combination with pectinase) is used to digest the cell wall and release the protoplast.

(D) In plant tissue culture,a $callus$ is defined as an unorganized,undifferentiated mass of proliferating plant cells. It is typically formed when plant explants (such as pieces of leaf,stem,or root) are cultured on a nutrient medium containing specific plant growth regulators (auxins and cytokinins). These cells are capable of further differentiation into various plant organs or whole plants.

(B) Statement $I$ is incorrect because colostrum is rich in antibodies (specifically $IgA$),not antigens.
Statement $II$ is incorrect because Chikungunya is caused by the Chikungunya virus,which is an $RNA$ virus,not a bacterium.
Statement $III$ is correct because meristematic tissues are free from viral infection,allowing the production of virus-free plants through tissue culture.
Statement $IV$ is incorrect because beer is produced by the fermentation of malted cereals (like barley) without distillation. Distillation is used for spirits like whiskey or brandy.
Therefore,only one statement $(III)$ is correct.

(A) Virus-free plants can be obtained through meristem culture.
This is because the meristematic tissue is a region of continuous cell division and growth.
In many plants,the virus cannot keep pace with the rapid rate of cell division in the meristem,making this zone free from viral infection.
Therefore,by culturing the apical or axillary meristem,healthy,virus-free plants can be regenerated.

(A) Virus-free plants can be obtained through $Meristem$ culture.
Even if a plant is infected with a virus, the $Meristem$ (apical and axillary) remains free of the virus because the virus cannot replicate in these rapidly dividing cells.
By isolating and culturing the $Meristem$ in vitro, we can produce healthy, virus-free clones of the parent plant.

(D) Tissue culture is a technique of growing plant cells,tissues,or organs in a sterile,artificial nutrient medium under controlled laboratory conditions.
To support the growth and development of the explant,the culture medium must contain essential nutrients.
These requirements include:
$1$. Inorganic salts (macro and micronutrients).
$2$. Carbon sources (e.g.,sucrose).
$3$. Vitamins and amino acids.
$4$. Growth regulators (phytohormones) such as auxins and cytokinins.
$5$. Solidifying agents like agar-agar (if a solid medium is required).
Since all the options listed are essential components of the culture medium,the correct answer is $D$.

(B) Haploid plants can be produced through tissue culture techniques by culturing pollen grains (microspores).
Since pollen grains are haploid ($n$ number of chromosomes),they develop into haploid plants,which are useful for plant breeding programs to create homozygous lines.

(D) The apical meristems are present in the apices of primary and secondary shoots and roots of the plant.
The cells of the apical meristem are in a very active stage of division,have dense cytoplasm,and thin cell walls.
Due to the rapid rate of cell division,the virus is unable to replicate and spread within these tissues,making the apical meristem typically virus-free.

(B) Root initiation in callus is the primary function of auxin. Cytokinins are responsible for promoting cell division,inducing shoot formation,and delaying the senescence of leaves and other organs.

(A) Cryopreservation is a technique used to preserve plant cells,tissues,or organs at very low temperatures. In this process,plant materials are stored in liquid nitrogen at $-196^{\circ} C$. This extremely low temperature stops all metabolic activities and prevents biological degradation,allowing the material to remain viable for a long period.

(D) Micropropagation is a technique of tissue culture used for the rapid multiplication of plants.
It involves the use of plant growth regulators,specifically auxins and cytokinins.
The ratio of auxins to cytokinins in the culture medium is critical as it determines the morphogenesis,such as root or shoot initiation,in the explant.

(C) Plant cell walls are primarily composed of cellulose,hemicellulose,and pectin.
To isolate a protoplast (a plant cell without a cell wall),the cell wall must be enzymatically degraded.
Cellulase is used to digest the cellulose component of the cell wall,while pectinase is used to break down the pectin component.
Therefore,a combination of both pectinase and cellulase is required for the effective isolation of protoplasts.

(B) Totipotency is the genetic potential of a plant cell to divide and differentiate into all the specialized cells of an organism,thereby regenerating a complete plant. This property is the fundamental basis of plant tissue culture.

(C) The method of growing or producing thousands of plants through tissue culture is called $Micropropagation$. In this process,a large number of plants are produced in a short duration using tissue culture techniques. Each of these plants will be genetically identical to the original plant from which they were grown,and they are called $Somaclones$.

(D) $G$ Haberlandt proposed the concept of cellular totipotency in $1902$. He suggested that every plant cell has the inherent potential to develop into a complete plant when cultured in an artificial nutrient medium under in vitro conditions. This foundational idea laid the basis for modern plant tissue culture.

(C) Healthy plants can be recovered from diseased plants by this method.
Apical and axillary meristem is the only virus-free part of a virus-infected plant.
By removing the meristem and growing it in vitro,virus-free plants can be obtained.

(A) In tissue culture,shoot regeneration is promoted by cytokinin,while root regeneration is promoted by auxins such as $NAA$ (Naphthalene Acetic Acid).
An excess of auxin relative to cytokinin promotes root development.
Conversely,a higher concentration of cytokinin relative to auxin promotes shoot regeneration.
Therefore,to induce roots,a higher concentration of auxins and a lower concentration of cytokinin are required.

(B) pollen grain is a male gametophyte that contains the male gametes. It is formed through meiosis and is therefore haploid $(n)$.
In tissue culture,when a single germinating pollen grain is cultured,it undergoes mitotic divisions to develop into an embryo and subsequently a plantlet.
Since the starting material (the pollen grain) is haploid,the resulting plant will also be haploid $(n)$.

(C) In plant tissue culture,an explant is defined as any part of a plant that is taken from the parent plant and placed into a nutrient medium for growth or regeneration. This can include pieces of leaves,stems,roots,or meristematic tissue.

(B) Hardening is the process of gradual acclimatization of plantlets produced through tissue culture to the external environment.
These plantlets are initially grown in a controlled,high-humidity,and low-light environment.
Before transferring them to the field,they are exposed to natural conditions slowly to ensure they can survive and adapt to the new environment.

(A) Protoplast fusion involves the removal of the plant cell wall to allow the fusion of two protoplasts. The plant cell wall is primarily composed of cellulose,hemicellulose,and pectin. Therefore,to digest the cell wall and isolate the protoplasts,a mixture of enzymes including $Cellulase$,$Hemicellulase$,and $Pectinase$ is required.

(A) Tissue culture is a technique of growing plant cells,tissues,or organs in a sterile environment on a nutrient medium.
The nutrient medium (such as Murashige and Skoog medium) must provide all the essential components for the growth and development of the explant.
These components include:
$1$. Carbon source: Sucrose is the most commonly used carbon source.
$2$. Inorganic salts: Essential for mineral nutrition (macro and micronutrients).
$3$. Growth regulators: Auxins and cytokinins are added to control morphogenesis and cell division.
$4$. Vitamins: Essential for metabolic processes.
$5$. Amino acids: Often added as a nitrogen source to support rapid growth.
Therefore,all the listed components ($I, II, III, IV$,and $V$) are required in the nutrient medium.

(C) Somaclonal variations refer to the genetic variations observed in plants regenerated from tissue culture.
These variations arise due to the stress of the culture environment,the use of growth regulators,or the duration of the culture period.
Since the plants produced through tissue culture are clones of the parent plant,any genetic change occurring during the process is termed a 'somaclonal variation'.
Therefore,the correct method for obtaining these variations is tissue culture.

(C) Somatic hybridization involves the fusion of protoplasts from two different species,which results in the formation of hybrids.
Naked protoplasts are obtained by the dissolution of their cell walls using macerating enzymes such as pectinase and cellulase.
The fusion of protoplasts from two different varieties can be enhanced by treating them with Polyethylene Glycol $(PEG)$ in the presence of a high-voltage electric current.

(D) Meristem culture is a technique used to produce virus-free plants from infected parent plants. By culturing the apical or axillary meristem,which is typically free of viruses,healthy plants can be regenerated. Examples of plants successfully developed using this technique include $Banana$,$Sugarcane$,and $Potato$.

(A) The method of producing thousands of plants through tissue culture is called micropropagation.
Each of these plants will be genetically identical to the original plant from which they were grown,i.e.,they are called somaclones.
Many important food plants like tomato,banana,apple,etc.,have been produced on a commercial scale using this method.

(D) Propagation by plant Tissue Culture (micropropagation) involves the propagation of plants by culturing cells,tissues,or organs.
Initially,the culturing of cells or tissues results in the formation of an undifferentiated mass of cells called $Callus$.
This $Callus$ later undergoes differentiation to produce a large number of plantlets.

(A) Micropropagation is a tissue culture technique used for the rapid multiplication of plants.
Since it involves vegetative propagation or cloning,the offspring produced are genetically identical to the parent plant.
These plants are referred to as 'true to type' because they maintain the exact genetic characteristics of the parent plant.
Therefore,the correct option is $A$.

(C) The capacity of a single plant cell to divide and differentiate into an entire new plant is known as $Totipotency$.
This biological phenomenon is the fundamental principle behind plant tissue culture and micropropagation.
$Reproduction$ is a broad term for producing offspring,$Budding$ is a specific type of asexual reproduction,and $Pleuripotency$ (or Pluripotency) refers to the ability of a cell to differentiate into many,but not all,cell types.

(C) Somaclonal variation refers to the genetic variations observed in plants that have been produced through tissue culture techniques.
These variations arise due to the stress of the culture environment,the use of growth regulators,or the duration of the culture period,leading to changes in the genetic makeup of the regenerated plants compared to the parent plant.
Therefore,plants raised in tissue culture are the ones that exhibit somaclonal variation.

(D) Micropropagation is a method of producing thousands of plants through tissue culture.
In this technique,the plants produced are genetically identical to the original plant from which they were grown.
Because these plants are genetically identical to the parent,they are referred to as somaclonal plants.

(B) The process of separating individual cells or small groups of cells from a callus (an unorganized mass of cells) to initiate a new culture is known as $Tissue \ culture$ or specifically $Cell \ culture$. In plant tissue culture,callus is induced from an explant,and these cells can be subcultured or isolated to study growth or regenerate plants.

(B) Pomato is a somatic hybrid produced by the fusion of protoplasts from potato ($Solanum$ $tuberosum$) and tomato ($Solanum$ $lycopersicum$). This process is known as somatic hybridization,which is a technique used in plant tissue culture to create new plant varieties by combining the genetic material of two different species.

(D) Plants are more easily manipulated by genetic engineering compared to animals due to the following reasons:
$(i)$ Totipotency: Plant cells possess the inherent ability to differentiate into all cell types,allowing for the regeneration of an entire organism.
$(ii)$ Regeneration: $A$ single somatic cell can regenerate a whole plant body,which is not typically possible with animal cells.
$(iii)$ Tissue Culture: Genetic engineering in plants is effectively supplemented by plant tissue culture techniques,which allow for the rapid multiplication of genetically modified cells.

(A) Somatic hybridization is a technique where somatic cells from two different plant species are fused to create a hybrid.
This process involves the isolation of protoplasts from the cells of the two plants.
The protoplasts are then fused using agents like $PEG$ (Polyethylene glycol) or electrofusion.
The resulting hybrid protoplast is then cultured to regenerate a whole plant,known as a somatic hybrid.
Therefore,the correct method is protoplast fusion.