Biotechnology
Biotechnology is any technique that uses living organisms or
substances derived from these organisms to make or modify a product, improve
plants or animals or develop microorganisms for specific uses” It ranges from traditional
biotechnology to most modern biotechnology
History
n The person who should be mentioned: Haberlandt, a plant
physiologist, is the first person performing the real plant tissue culture
experiment, and the time was 1902.
Theory
n Theory for plant cell and tissue culture: the totipotency, which
states that cells are autonomic, and in principle, are capable of regenerating
to give a complete plant.
n Plant tissue culture is defined as culture under sterile
conditions, of plants, seeds, embryos, organs, tissues, cells and protoplasts.
Characteristics of Plant Tissue Culture Techniques
- Occur on a micro-scale.
- Environmental conditions optimized (nutrition, light, temperature, phytochemistry).
- All microbes (fungi, bacteria, viruses, and nematodes are excluded).
- The normal pattern of plant development breaks down giving rise to callus, adventitious roots, shoots, and/or embryos.
- Ability to grow as single cells (protoplasts, microspores, suspension cultures)
- Plant cells are totipotent (e.g.: able to regenerate a whole plant).
Uses of Plant Cell and Tissue Culture
n Production of pathogen free plants
n Meristem Culture
n Somatic embryogenesis
n Organ Culture Callus Culture
n Anther and pollen grain Culture (Haploid production)
n Protoplast culture
n Germplasm preservation
Main Objectives
n Elimination of viruses from infected plants
n Rapid multiplication of clones
n Vegetative propagation of difficult to propagate species
n All the year round propagation of clones
n Rapid multiplication of seedlings (in cases where seed is hard
to get
n Virus Eradication
n Disinfest plant material and culture buds;
n Discard contaminated field taken material /cultures and rear
aseptic cultures until they are small plants; or
n Expose these field taken material/aseptic plants to elevated
temperatures (34-37 oC) during incubation for various times.
n Excise small stem tips from these incubated plants and incubate
in culture at 25°C;
n Incubate until each plant is quite large and test for presence
of viruses;
n If free of detectable viruses, re-culture from this (or these)
plant(s) and multiply to obtain a population of virus-free clonal material.
n Meristem tip refers to the region of shoot apex lying distal to
the youngest leaf primordial, whereas shoot apex includes Meristem tips plus a
few sub adjacent leaf primordial.
n Enhanced axillary shoot proliferation
n Node culture,
n de novo formation of adventitious shoot through shoot
organogenesis,
n Nonzygotic embryogenesis.
Advantages of Micropropagation
n Plant material require less attention between subcultures and
there is no labour or material requirement for watering, weeding, spraying,
etc. Micropropagation is most advantageous where costs is less than traditional
methods of multiplication.
n Certified virus free plants can be produced in large number.
n It is possible to produce clones of same kinds of plants that
are otherwise slow and difficult to propagate vegetative.
n Only limited space is required to maintain and produce large
number of plants.
n Plants may acquire a temporary vigor through micropropagation
which makes them more desirable to the grower than conventionally raised stock.
n Production can be continued all the year round and is
independent of seasonal changes.
n Plants may acquire a temporary vigor through micropropagation
which makes them more desirable to the grower than conventionally raised stock.
n Production can be continued all the year round and is
independent of seasonal changes.
n Propagation is ideally carried out under aseptic conditions,
free from pathogens. Once culture have been started there should be no loss through
disease and the plantlets finally produced should be free from bacteria, fungi
and other microorganisms.
n Somatic embryogenesis is the production of embryos from somatic
or “non-germ” cells.
n Not a common micropropagation technique but is currently being
used to produce superior spruce seedlings here in B.C.
n Usually involves a callus intermediate stage which can result in
variation among seedlings
Organogenesis
n This is the production of roots, shoots or leaves.
n These organs may arise out of pre-existing meristems or out of
differentiated cells.
n This, like embryogenesis, may involve a callus intermediate but
often occurs without callus.
n Both of these technologies can be used as methods of micropropagation.
n Not always desirable because they may not always result in
populations of identical plants.
n The most beneficial use of somatic embryogenesis and
organogenesis is in the production of whole plants from a single cell (or a few
cells).
n Callus is an unorganized mass of cell which can be induce to
re-differentiate on appropriate medium to develop embryoids which directly
develop into plantlets, eventually giving rise to a whole viable plant.
n The culture of immature anthers and pollen grains is done so as
to induce the pollen grains to develop into multicellular forms, particularly
into embryos, with half the normal
number of chromosomes for the species.
n When such haploid embryos
are treated with chromosome doubling agents, e.g. colchicines, their normal chromosome number is restored (and
thus their fertility) and, in addition, the plants are pure lines.
n Enzymatic removal of the mainly cellulose wall surrounding a
plant cell results in a protoplast. When these are cultured, a new wall is
synthesized thus restoring the original state of the plant cell. However,
during the period that the protoplast is wall-less, there is the possibility:-
n Of adding foreign genetic material to the protoplast,
n Of fusing the protoplasts of two cultivars or even species to
form hybrid cells.
n The preservation of Germplasm in vitro by tissue culture
is an extension of micropropagation techniques.
n Simply it is that by the micropropagation techniques
scientists get plant materials to be
conserved. Then by the same techniques they make these materials grow slowly in
the culture room and keep their genetic characteristics stable
Banana
In Pakistan, experimental banana cultivation was started
after Independence, and soon after its success in Sindh the banana emerged as
an important fruit crop. It is now grown
on 30.3,000 ha with a total annual production of 139.5,000 metric tons.
Overview
Area (Pakistan) =
30,300 hectare
Production =
1,39,500 tones
Distribution = Sindh (86.8%), Punjab (8.6%),
Balochistan(3.0%),
NWFP (2.0%)
VARIETY
Locally called Bombay
Dwarf Cavendish (95%)
William hybrid (3%)
n Media Preparation Area/Room
n Aseptic transfer Chamber Area
n Environmentally Controlled Culture Room
n Analytical Room and Acclimatization Room
Conclusion
The application of tissue culture techniques has helped
breeders to improve varieties more efficiently, and the breeders are able to
handle the crops in such a new way that they were unable to do with
conventional methods only. For many agronomic and horticultural crops, tissue
culture can accelerate growth of seeds and seedlings which contributes directly
to an improved agricultural production.
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