Plant Tissue Culture Notes

Assertion-Reason

Assertion: Aseptic conditions are absolutely essential for a successful tissue culture experiment.

Reason: The nutrient-rich medium used for tissue culture is also an ideal growth environment for contaminating microorganisms like bacteria and fungi.

Assertion-Reason

Assertion: The use of a laminar air flow cabinet is mandatory for all inoculation procedures.

Reason: A laminar air flow cabinet maintains a sterile, contamination-free workspace by continuously filtering the air.

Assertion-Reason

Assertion: Explant sterilization is not required if the explant is taken from the internal tissue of the plant.

Reason: Although internal tissues are generally sterile, surface contaminants can be introduced during the dissection process.

Assertion-Reason

Assertion: Sucrose is added to the nutrient medium in plant tissue culture.

Reason: Cultured plant cells are heterotrophic and cannot produce their own food.

Assertion-Reason

Assertion: Acclimatization is a short process that can be skipped for hardy plant species.

Reason: Plantlets from tissue culture are very sensitive to low humidity and sudden environmental changes, regardless of the species' natural hardiness.

Question: The ability of a single cell to give rise to a whole new plant is known as:

• Callus formation
• Organogenesis
• Totipotency
• Micropropagation

Question: The unorganized mass of undifferentiated cells formed during plant tissue culture is called:

• Explant
• Meristem
• Callus
• Zygote

Question: The process of transferring a plantlet from the lab to a natural environment is called:

• Inoculation
• Hardening
• Organogenesis
• Acclimatization

Question: Which of the following is most commonly used as a carbon source in the nutrient medium?

• Glucose
• Fructose
• Sucrose
• Lactose

Question: A laminar air flow hood is used to ensure:

• Proper light exposure
• Sterility
• Temperature control
• pH regulation

Question: The part of the plant taken for tissue culture is called:

• Callus
• Plantlet
• Protoplast
• Explant

Question: Plant cells in culture are typically:

• Autotrophic
• Heterotrophic
• Phototropic
• Chemotrophic

Question: What is the primary purpose of agar in the culture medium?

• Nutrient source
• Gelling agent
• Carbon source
• Hormone

Question: Which of these is NOT a stage of the basic tissue culture process?

• Inoculation
• Insemination
• Sterilization
• Acclimatization

Question: Hardening is the process of:

• Making the medium solid
• Making the plantlet durable
• Sterilizing the explant
• Promoting root growth

Assertion-Reason

Assertion: A high concentration of cytokinin relative to auxin in the medium promotes shoot formation.

Reason: Cytokinins are primarily responsible for cell division and breaking apical dominance.

Assertion-Reason

Assertion: An equal ratio of auxin to cytokinin promotes callus formation and growth.

Reason: Both hormones are needed in balanced amounts to keep the cells in an undifferentiated, dividing state.

Assertion-Reason

Assertion: Gibberellins are commonly used to induce root formation in tissue culture.

Reason: Gibberellins' primary role is promoting shoot elongation, while auxins are responsible for rooting.

Assertion-Reason

Assertion: The addition of Abscisic Acid (ABA) to the medium can inhibit somatic embryogenesis.

Reason: ABA acts as a stress hormone and can prevent the formation of somatic embryos.

Assertion-Reason

Assertion: Auxins must always be used in combination with cytokinins for any tissue culture to be successful.

Reason: Some tissue cultures, particularly for rooting, can succeed with only auxins present.

Question: If a callus is transferred to a medium with a high concentration of auxin and a low concentration of cytokinin, it will most likely form:

• Shoots
• Roots
• A new callus
• Leaves

Question: The growth regulator responsible for promoting cell division and shoot differentiation is:

• Auxin
• Gibberellin
• Abscisic acid
• Cytokinin

Question: The process of forming unorganized, undifferentiated cells is triggered by:

• High auxin concentration
• High cytokinin concentration
• Balanced auxin and cytokinin concentration
• Lack of hormones

Question: Which hormone would you use to promote elongation of shoots?

• Auxin
• Gibberellin
• Cytokinin
• Abscisic acid

Question: What is a common function of auxin in tissue culture?

• Root formation
• Shoot multiplication
• Breaking dormancy
• Promoting flowering

Question: What is the primary role of cytokinins?

• Cell elongation
• Root initiation
• Cell division
• Dormancy

Question: Which hormone is a growth inhibitor?

• Auxin
• Gibberellin
• Cytokinin
• Abscisic acid

Question: If you want to produce only callus from an explant, which hormone ratio is best?

• High Auxin
• High Cytokinin
• Equal ratio of both
• No hormones

Question: What is the common role of Abscisic Acid (ABA) in culture?

• Shoot induction
• Preventing callus growth
• Inducing callus growth
• Promoting somatic embryogenesis

Question: Which hormone class is crucial for organogenesis?

• Auxins and Cytokinins
• Gibberellins and ABA
• Auxins only
• Cytokinins only

Assertion-Reason

Assertion: Somatic hybridization is a method of overcoming sexual incompatibility between species.

Reason: It bypasses the need for gamete fusion and fertilization by fusing the somatic cells of two different plants.

Assertion-Reason

Assertion: Somatic hybrids can sometimes be sterile or unstable.

Reason: The fusion of genomes from distantly related species can lead to genetic instability and sterility.

Assertion-Reason

Assertion: PEG is a common agent used for inducing protoplast fusion.

Reason: PEG causes dehydration, bringing the protoplast membranes closer to each other, facilitating fusion.

Assertion-Reason

Assertion: Cybrids are plants that possess the combined nuclear and cytoplasmic genome of two parental species.

Reason: Cybrids only contain the nuclear genome of one parent and the cytoplasmic genome (mitochondria, chloroplasts) of the other.

Assertion-Reason

Assertion: Somatic hybridization has successfully created many commercially important crop varieties.

Reason: While a powerful research tool, creating commercially viable crops through somatic hybridization remains a challenge due to issues like hybrid instability.

Question: The enzymes used for isolating protoplasts are:

• Amylase and Protease
• Lipase and Cellulase
• Pectinase and Cellulase
• Sucrase and Cellulase

Question: Which of the following is NOT a fusogen?

• PEG
• Calcium ions
• Sucrose
• Electrical stimulation

Question: A somatic hybrid that has the nucleus from one parent and cytoplasm from both is called a:

• Homokaryon
• Cybrid
• Symmetric hybrid
• Chimeric plant

Question: The first somatic hybrid produced was:

• Pomato
• Broccoflower
• Cabbage x Radish
• Potato x Tomato

Question: Which of the following is an advantage of somatic hybridization?

• It guarantees fertile hybrids.
• It can cross sexually incompatible species.
• It is a simpler method than conventional breeding.
• It produces genetically uniform offspring.

Question: Somatic hybridization is an example of:

• Sexual reproduction
• Asexual reproduction
• A form of genetic engineering
• A form of mutation breeding

Question: The primary reason for performing somatic hybridization is:

• To increase seed production
• To improve nutrient uptake
• To transfer desirable traits
• To reduce plant size

Question: A major limitation of somatic hybridization is:

• Difficulty in callus formation
• High cost of chemicals
• Unstable hybrids and genetic segregation
• Difficulty in protoplast isolation

Question: Protoplasts are plant cells without a:

• Cell membrane
• Nucleus
• Mitochondria
• Cell wall

Question: In electrofusion, what is used to cause protoplasts to fuse?

• Heat
• Enzymes
• Low voltage electrical pulses
• High pressure

Assertion-Reason

Assertion: Anther culture is a method to produce haploid plants.

Reason: Anthers contain microspores (pollen grains) which are haploid.

Assertion-Reason

Assertion: The use of colchicine is essential for converting haploid plants to fertile diploid plants.

Reason: Colchicine inhibits spindle fiber formation during mitosis, leading to a doubling of the chromosome number.

Assertion-Reason

Assertion: Haploid plants are a valuable tool in plant breeding.

Reason: They allow for the rapid creation of homozygous pure lines, which can speed up breeding programs.

Assertion-Reason

Assertion: Pollen culture is always preferred over anther culture.

Reason: Anther culture is sometimes simpler and can be a good starting point, but pollen culture avoids the risk of callus formation from somatic tissues of the anther wall.

Assertion-Reason

Assertion: Pollen culture is a form of sexual reproduction.

Reason: It is an asexual, in vitro propagation method that does not involve the fusion of gametes.

Question: The development of a haploid plant from a microspore is called:

• Androgenesis
• Gynogenesis
• Polyploidy
• Parthenogenesis

Question: Haploid plants contain:

• A single set of chromosomes
• A double set of chromosomes
• A triple set of chromosomes
• No chromosomes

Question: The substance used to double the chromosome number of haploid plants is:

• Auxin
• Cytokinin
• Gibberellin
• Colchicine

Question: What is a major advantage of haploid plant production?

• Increased yield
• Rapid development of homozygous lines
• Disease resistance
• Drought tolerance

Question: Which of the following is a major challenge with haploid plants?

• They are highly fertile.
• They are sterile and have low vigor.
• They are resistant to all diseases.
• They grow very slowly.

Question: Anther culture is a form of:

• Sexual reproduction
• Asexual reproduction
• Polyploidy
• Genetic modification

Question: What is the primary objective of anther/pollen culture?

• To produce genetically identical plants
• To produce plants with improved yield
• To produce haploid plants
• To produce virus-free plants

Question: In androgenesis, the callus or embryo originates from the:

• Anther wall
• Connective tissue
• Microspore
• Filament

Question: What kind of cells are the microspores in an anther?

• Somatic cells
• Diploid cells
• Haploid cells
• Triploid cells

Question: Why are haploid plants treated with colchicine?

• To induce rooting
• To promote shoot growth
• To restore fertility
• To increase size

Assertion-Reason

Assertion: Cryopreservation is an ideal method for long-term storage of plant germplasm.

Reason: At ultra-low temperatures, all biological processes cease, allowing for indefinite storage without degradation.

Assertion-Reason

Assertion: Cryoprotectants are essential in cryopreservation to prevent ice crystal formation.

Reason: Cryoprotectants lower the freezing point and increase the viscosity of the solution, which promotes vitrification and prevents lethal ice formation inside cells.

Assertion-Reason

Assertion: Vitrification is the process of slow freezing.

Reason: Vitrification involves rapid, flash-freezing to turn water into a glassy state, while slow freezing is a gradual process.

Assertion-Reason

Assertion: Thawing of cryopreserved material should be done slowly to avoid shock to the cells.

Reason: Rapid thawing is preferred to minimize the time spent in the critical temperature zone where ice recrystallization can occur.

Assertion-Reason

Assertion: Cryopreservation is used for both orthodox and recalcitrant seeds.

Reason: It is primarily used for recalcitrant seeds which cannot withstand conventional drying and storage, while orthodox seeds are stored dry.

Question: The most common temperature used for cryopreservation is:

• $-20^\circ C$
• $-80^\circ C$
• $-196^\circ C$
• $0^\circ C$

Question: Which of the following is a common cryoprotectant?

• Sucrose
• Glycerol
• Agar
• Mannitol

Question: What is the primary danger to cells during cryopreservation?

• Nutrient depletion
• Ice crystal formation
• Bacterial contamination
• Light damage

Question: The term 'vitrification' refers to:

• Slow freezing
• Rapid freezing to a glassy state
• Rehydration of cells
• The use of vitamins

Question: Cryopreservation is a key tool for:

• Enhancing crop yield
• Improving flavor
• Genetic conservation
• Creating new hybrids

Question: Liquid nitrogen is a suitable medium for cryopreservation because:

• It is inexpensive
• It allows cells to grow slowly
• It stops all metabolic activity
• It kills all pathogens

Question: Which type of seed is most likely to be cryopreserved?

• Orthodox seeds
• Recalcitrant seeds
• Genetically modified seeds
• Hybrid seeds

Question: What is the primary goal of using a cryoprotectant?

• To add nutrients
• To prevent freezing injury
• To increase cell size
• To promote dormancy

Question: At what temperature is liquid nitrogen stored?

• $-20^\circ C$
• $-70^\circ C$
• $-196^\circ C$
• $0^\circ C$

Question: Thawing of cryopreserved material is typically:

• Slow and controlled
• Rapid
• Done at room temperature
• Done in a freezer