Internship

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Micropropagation
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Micropropagation

• Art and Science of multiplying plants in vitro

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Tissue culture is the initial step of
micropropagation where plant cells are grown in
an artificial medium, developing them into a
large number of plantlets.
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What is plant tissue culture?

• Plant tissue culture is a technique of growing
  plant cells, tissues, organs, seeds or other
  plant parts in a sterile environment on a
  nutrient medium

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Terms Used in Plant Tissue Culture

• Explant
• An excised piece of differentiated tissue or
  organ is regarded as an explant. The explant may
  be taken from any part of the plant body e.g.,
  leaf, stem, root.
• Callus
• The unorganized and undifferentiated mass of
  plant cells is referred to as callus. Generally,
  when plant cells are cultured in a suitable
  medium, they divide to form callus i.e., a mass
  of parenchymatous cells.

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Terms Used in Tissue Culture

• Dedifferentiation
• The phenomenon of mature cells reverting to
  meristematic state to produce callus is
  dedifferentiation. Dedifferentiation is possible
  since the non- dividing quiescent cells of the
  explant, when grown in a suitable culture medium
  revert to meristematic state.
• Re-differentiation
• The ability of the callus cells to differentiate
  into a plant organ or a whole plant is regarded
  as re-differentiation.

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Basic Technique of Plant Tissue Culture
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Tissue Culture Basics
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In many cases, older tissue will not form callus
younger tissue easier to surface disinfect
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EXPLANT SIZE

• the smaller the explant, the harder it is to
  culture.
• The larger explants probably contain more
  nutrient reserves and plant growth regulators to
  sustain the culture.

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PLANT QUALITY

• It is advisable to obtain explants from plants
  which are healthy as compared to plants under
  nutritional or water stress or plants which are
  exhibiting disease symptoms.

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GOAL

• Depending on what type of a response is desired
  from the cell culture, the choice of explant
  tissue will vary.

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• For example, if clonal propagation is the goal,
  then the explant will usually be a lateral or
  terminal bud or shoot.
• For callus induction, pieces of the cotyledon,
  hypocotyl, stem, leaf, or embryo are usually
  used.
• Excellent explants for callus induction are
  seedling tissues from aseptically germinated
  seeds or immature inflorescences.
• Leaf tissue from the aseptically germinated seed
  is a good source of tissue for protoplast
  isolation.
• To produce haploid plants or callus, the anther
  or pollen is cultured.

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Application of micropropagation

• Mass clonal multiplication of desirable genotypes
  of plants.
• Plant can multiply irrespective of season
• In vitro conservation and propagation of
  endangered species.
• Production of disease free plant through
  meristem culture

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Application of micropropagation

• Through tissue culture, over a million plants can
  be grown from a small piece of plant tissue
  within 12 months.

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Advantages of micropropagation

• Short span of time and space large number of
  plant can be produced starting from a single
  individual.
• Minimum growing space required
• Rapid efficient propagation
• Long-term germplasm storage
• Production of difficult-to-propagate species

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Disadvantages

• Equipment/facility intensive operation
• Technical expertise
• Protocols not optimized for all species
• It may be too expensive