Micropropagation for Large-Scale Production of Medicinal Plants, Tree Species and Ornamentals –
1. Introduction
Micropropagation is an in-vitro clonal propagation technique used for rapid multiplication of plants under aseptic and controlled laboratory conditions. It enables the production of a large number of genetically uniform, disease-free plants from a small amount of starting material (explant).
This technique is especially important for medicinal plants, forest tree species and ornamental plants, where conventional propagation is slow, seasonal or inefficient.
2. Principle of Micropropagation
Micropropagation is based on totipotency, the inherent ability of a single plant cell to regenerate into a complete plant when provided with:
Suitable nutrient medium
Proper plant growth regulators
Controlled light, temperature and humidity
Sterile conditions.
3. Stages of Micropropagation
Micropropagation generally involves five stages:
Stage I – Selection and Sterilization of Explant
Healthy, elite, disease-free mother plants are selected.
Common explants:
Apical meristems
Axillary buds
Nodal segments
Leaf or root segments
Surface sterilization using alcohol and chemical sterilants.
Aim: Establishment of aseptic culture.
Stage II – Initiation of Culture
Explant is inoculated onto nutrient medium (usually MS medium).
Medium contains:
Macronutrients and micronutrients
Vitamins
Carbon source (sucrose)
Growth regulators
Cytokinins stimulate shoot initiation.
Stage III – Multiplication
Repeated subculturing leads to rapid shoot proliferation.
High cytokinin concentration promotes:
Multiple shoot formation
Axillary bud proliferation
This stage ensures large-scale production.
Stage IV – Rooting
Shoots are transferred to rooting medium.
Auxins such as IBA, IAA or NAA promote root development.
Complete plantlets are formed.
Stage V – Hardening (Acclimatization)
In-vitro plantlets are gradually exposed to external conditions.
Plantlets are transferred to:
Greenhouses
Polyhouses
Nurseries
Essential for survival under field conditions.
4. Culture Media Used
Murashige and Skoog (MS) Medium
Components:
Macronutrients: N, P, K, Ca, Mg
Micronutrients: Fe, Zn, Mn, Cu
Vitamins: Thiamine, Nicotinic acid
Carbon source: Sucrose
Gelling agent: Agar
5. Micropropagation of Medicinal Plants
Importance
Many medicinal plants show:
Poor seed viability
Slow growth
Over-exploitation from nature
Micropropagation helps in conservation and mass multiplication.
Examples
Aloe vera
Rauvolfia serpentina
Withania somnifera (Ashwagandha)
Neem (Azadirachta indica)
Catharanthus roseus
Ocimum sanctum (Tulsi)
Advantages
Uniform production of bioactive compounds
Disease-free planting material
Conservation of endangered medicinal species
6. Micropropagation of Tree Species
Importance
Trees have:
Long life cycle
Poor seed germination
Seasonal seed availability
Micropropagation provides rapid clonal multiplication.
Examples
Teak (Tectona grandis)
Eucalyptus
Populus
Pine
Bamboo
Applications
Afforestation and reforestation programs
Production of elite forestry clones
Conservation of rare tree species
7. Micropropagation of Ornamental Plants
Importance
Ornamentals require:
Uniform growth
Consistent flower colour and shape
Conventional methods are slow and seasonal.
Examples
Orchid
Rose
Chrysanthemum
Gerbera
Carnation
Anthurium
Benefits
Year-round production
Rapid multiplication of elite varieties
High commercial value
8. Methods Used in Micropropagation
Meristem culture
Axillary bud culture
Callus culture
Adventitious shoot formation
Somatic embryogenesis
9. Advantages of Micropropagation
Rapid large-scale multiplication
Genetically uniform plants
Disease-free planting material
Requires small space
Conservation of endangered species
Year-round production
10. Limitations of Micropropagation
High cost of laboratory setup
Skilled manpower required
Risk of somaclonal variation
Contamination problems
Not suitable for all plant species
11. Applications
Commercial production of medicinal plants
Forestry and plantation programs
Floriculture industry
Germplasm conservation
Biotechnology and genetic improvement programs
12. Conclusion
Micropropagation plays a crucial role in the large-scale production of medicinal plants, tree species and ornamentals. It ensures rapid multiplication, genetic uniformity, disease-free plants and conservation of valuable plant resources, making it an essential tool in modern agriculture, forestry and horticulture.
Micropropagation – 50 MCQs with Answers
Micropropagation is the technique of
A. Seed propagation
B. Vegetative propagation in soil
C. In vitro clonal propagation
D. Sexual reproduction
Answer: C
The basic principle of micropropagation is
A. Mutation
B. Hybridization
C. Totipotency
D. Polyploidy
Answer: C
Totipotency refers to
A. Ability of cell division
B. Ability to mutate
C. Ability of a single cell to regenerate into a whole plant
D. Ability to photosynthesize
Answer: C
The most commonly used explant for micropropagation is
A. Root tip
B. Leaf margin
C. Shoot tip / meristem
D. Anther
Answer: C
Culture medium most widely used in micropropagation is
A. White’s medium
B. Knop’s medium
C. MS medium
D. B5 medium
Answer: C
MS medium was developed by
A. White
B. Gamborg
C. Murashige and Skoog
D. Nitsch
Answer: C
The major plant growth regulator used for shoot multiplication is
A. Auxin
B. Gibberellin
C. Cytokinin
D. Ethylene
Answer: C
Auxins mainly promote
A. Shoot formation
B. Root formation
C. Flowering
D. Dormancy
Answer: B
Cytokinins commonly used in micropropagation include
A. IAA and IBA
B. GA₃
C. BAP and kinetin
D. Ethrel
Answer: C
Stage I of micropropagation involves
A. Rooting
B. Hardening
C. Establishment of explant
D. Callus induction
Answer: C
Stage II of micropropagation is
A. Acclimatization
B. Shoot multiplication
C. Rooting
D. Transplantation
Answer: B
Stage III of micropropagation is
A. Shoot induction
B. Root induction
C. Hardening
D. Explant selection
Answer: B
Stage IV of micropropagation involves
A. Shoot elongation
B. Rooting
C. Hardening and acclimatization
D. Callus formation
Answer: C
Hardening is necessary to
A. Increase mutation
B. Kill contaminants
C. Adapt plantlets to field conditions
D. Increase chlorophyll
Answer: C
The main advantage of micropropagation is
A. Genetic variation
B. Seasonal dependence
C. Rapid multiplication of true-to-type plants
D. High cost
Answer: C
Micropropagation is especially useful for
A. Annual crops only
B. Medicinal plants with low seed viability
C. Weeds
D. Self-pollinated crops
Answer: B
A major limitation of micropropagation is
A. Slow growth
B. High cost and contamination
C. Low yield
D. Field dependence
Answer: B
Somaclonal variation arises due to
A. Meiosis
B. Fertilization
C. Prolonged tissue culture
D. Pollination
Answer: C
Micropropagation of medicinal plants helps in
A. Loss of biodiversity
B. Overexploitation
C. Conservation of elite genotypes
D. Reduced yield
Answer: C
Example of a medicinal plant micropropagated widely is
A. Wheat
B. Rice
C. Aloe vera
D. Maize
Answer: C
Tree species commonly micropropagated include
A. Mango and banana
B. Teak and eucalyptus
C. Rice and wheat
D. Cotton and jute
Answer: B
Micropropagation of trees is difficult due to
A. Fast growth
B. Recalcitrant nature and long life cycle
C. High seed set
D. Easy rooting
Answer: B
Ornamentals are micropropagated mainly for
A. Food value
B. Timber
C. Uniformity and disease-free plants
D. Oil content
Answer: C
A commonly micropropagated ornamental plant is
A. Rice
B. Wheat
C. Orchid
D. Mustard
Answer: C
Micropropagation ensures disease-free plants by
A. Chemical treatment
B. Heat treatment
C. Meristem culture
D. Mutation
Answer: C
Meristem culture is effective against
A. Fungi
B. Bacteria
C. Viruses
D. Nematodes
Answer: C
Agar is used in tissue culture as
A. Nutrient
B. Hormone
C. Gelling agent
D. Preservative
Answer: C
pH of culture medium is usually maintained around
A. 3.0
B. 4.0
C. 5.6–5.8
D. 7.5
Answer: C
Surface sterilization of explants is done using
A. Fertilizers
B. Mercuric chloride / sodium hypochlorite
C. Sucrose
D. Agar
Answer: B
Light requirement during culture is
A. Complete darkness always
B. Natural sunlight only
C. Controlled photoperiod
D. No light
Answer: C
Micropropagation helps conserve endangered medicinal plants by
A. Field cultivation
B. Seed banks
C. Ex situ conservation
D. Pollination
Answer: C
The main carbon source in culture medium is
A. Agar
B. Glucose
C. Sucrose
D. Fructose
Answer: C
Callus is
A. Organized tissue
B. Unorganized mass of cells
C. Meristem
D. Root tip
Answer: B
Organogenesis refers to
A. Embryo formation
B. Callus growth
C. Formation of organs like shoot and root
D. Cell division
Answer: C
Somatic embryogenesis produces
A. Seeds
B. Roots
C. Embryo-like structures from somatic cells
D. Flowers
Answer: C
Somatic embryos differ from zygotic embryos because they
A. Have endosperm
B. Are formed after fertilization
C. Lack seed coat and endosperm
D. Are diploid only
Answer: C
Bioreactors are used in micropropagation for
A. Sterilization
B. Hardening
C. Mass multiplication of plantlets
D. Seed storage
Answer: C
Synthetic seeds are produced from
A. Zygotic embryos
B. True seeds
C. Somatic embryos
D. Pollen grains
Answer: C
A major benefit of micropropagation in ornamentals is
A. Genetic diversity
B. Long duration
C. Year-round production
D. Low survival
Answer: C
Eucalyptus micropropagation is important for
A. Medicinal use
B. Ornamental value
C. Pulp and paper industry
D. Food crops
Answer: C
Clonal fidelity means
A. Genetic variation
B. Mutation
C. Genetic uniformity of propagated plants
D. Hybrid vigor
Answer: C
The success of micropropagation depends on
A. Soil type
B. Rainfall
C. Genotype and culture conditions
D. Pollination
Answer: C
Contamination in tissue culture is mainly due to
A. Hormones
B. Agar
C. Microorganisms
D. Light
Answer: C
Micropropagation reduces pressure on
A. Laboratories
B. Industries
C. Natural plant populations
D. Farmers
Answer: C
Banana is commonly micropropagated because
A. Seeds are abundant
B. It is vegetatively propagated
C. It is a tree crop
D. It has dormancy
Answer: B
One disadvantage of micropropagation is
A. Rapid growth
B. Disease-free plants
C. Somaclonal variation
D. Uniformity
Answer: C
Micropropagation is independent of
A. Sterile conditions
B. Culture medium
C. Seasonal constraints
D. Growth regulators
Answer: C
Which hormone combination favors shoot proliferation?
A. High auxin : low cytokinin
B. Equal auxin and cytokinin
C. High cytokinin : low auxin
D. Only auxin
Answer: C
The final transfer of plantlets to soil is called
A. Subculturing
B. Inoculation
C. Transplantation
D. Multiplication
Answer: C
Micropropagation plays a key role in
A. Soil fertility
B. Hybrid seed production
C. Commercial horticulture and forestry
D. Pest control
Answer: C
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