PLANT CELL AND TISSUE CULTURE Flashcards
Why Plant tissue culture offers numerous significant benefits over traditional propagation methods?
-Much faster rates of growth can be induced in vitro than by traditional means,
-It may be possible to multiply in vitro plants that are very
difficult to propagate by cuttings or other traditional methods
- Tissue culture techniques are used for virus eradication, genetic manipulation, somatic hybridization and other procedures that benefit propagation, plant improvement, and basic research
Advantages of plant culturing
-A lot of new plants can be grown in a relatively short time
-Little space is needed, and conditions can be precisely controlled
-All new plants inherit the same desirable characteristics
Disadvantages of plant culturing
-All plants have the same genetic make-up - so will all be vulnerable to same diseases or pests
-No chance of new beneficial characteristics arising by chance
-No variation means there is a danger of reducing the gene pool
Three basic components of culture media
-Essential elements, or mineral ions.
-An organic supplement.
-A source of fixed carbon.
Essential elements are:
1) Macroelements (or macronutrients);
2) microelements (or micronutrients)
3) an iron source
Component of proteins, nucleic acids and some coenzymes Element required in greatest amount
Nitrogen
Regulates osmotic potential, principal inorganic cation
Potassium
Cell wall synthesis, membrane function, cell signalling
Calcium
Component of nucleic acids, energy transfer, component of intermediates in respiration and photosynthesis.
Phosphorus
An Auxin, its use in plant cell culture media is limited because it is unstable to both heat and light.
IAA
The regeneration of whole organisms depends upon the concept that all plant cells can express the total genetic potential of the parent plant
Totipotency
Allows one type of tissue or organ to be initiated from another type.
Plasticity
They are involved in regulating cell elongation, and are agronomically important in determining plant height and fruit-set.
gibberellins
It is most commonly used in plant tissue culture to promote distinct developmental pathways such as somatic embryogenesis.
Abscisic Acid
A gaseous, naturally occurring, plant growth regulator most commonly associated with controlling fruit ripening, and its use in plant tissue culture is not widespread
Ethylene
aspects decide the size of explant
The surface size.
Volume.
Cell number.
The most popular source of explants to initiate tissue cultures.
Shoot-tips and meristem-tips
This consists of a piece of stem with axillary bud culture with or without a portion of shoot.
-Such explants are not commonly used in commercial propagation.
Nodal or Axillary Bud Culture
The most popular method of monocot plant regeneration.
Immature, embryo-derived embryogenic callus
The embryo removal procedure is performed aseptically by using stereomicroscope equipped with a cool fluorescent lamp
Isolation of Embryo
young embryos may prove difficult to culture directly on the medium. In such cases, embryos may be implanted into developing endosperm
embryo-nurse endosperm technique
It is an unorganized or undifferentiated mass of cells produced either in culture or in nature.
Callus
Media without growth regulators
Habituation
There are three types of suspension cultures
batch culture
continuous culture (closed and open)
immobilized cell cultures
It is a suspension culture where the cell cultures are maintained in a definite volume of agitated liquid with repeated subculturing of a small aliquot of cell culture to a fresh medium at regular intervals.
Batch culture
The cell population is maintained in a steady state by regularly replacing a portion of the used or spent medium by fresh medium
Continuous culture/mass culture
Assessment of cells in suspension
Cell count
Packed Cell Volume
Cell Fresh Weight
Plant cells may be encapsulated in a suitable material ( in membranes or stainless screens).
Immobilized cell cultures
Refers to the percentage of cells undergoing mitosis.
Mitotic Index (MI)
The entire plant cell without its cellulosic cell wall
Protoplast
Sources of Protoplast
- mesophyll cells of leaves
- cultured suspension cells
- callus culture
- preconditioned plant material
It is a solution causing changes in osmatic pressure.
Osmoticum
The first to report the direct development of embryos form pollen grains of Datura by anther culture
Guha and Maheswari (1964)
in vitro development of haploid plants originating from totipotent pollen grains through a series of cell division and differentiation.
What is Androgenesis
The basic principle is the production of haploid plants using the totipotency of microspore and the occurrence of single set of chromosome (n) in microspore.
anther and pollen culture
may be isolated either by squeezing or float or Slit technique culture of anthers
Pollen
Chromosomes Doubling In Haploid?
- Spontaneous duplication
- Induced duplication: by Colchicine treatment
Culture of unfertilized ovaries to obtain haploid plants from egg cell or other haploid cells of embryo sac
Ovary Culture
When haploid plants originate from other than egg cell called synergid (rice) or antipodal (Allium tuberosum)
In vitro Apogamy
Is the formation of Haploid plants from egg cell in most of species (rice).
In vitro Parthenogenesis
The production of multiple copies of a single plant using tissue culture techniques or it is the in vitro regeneration of plants from organs, tissues, cells or protoplasts
Micropropagation
Stages in Micropropagation
Stage 0 – Preparative stage
Stage I – initiation of aseptic culture
Stage II – shoot proliferation stage
Stage III – root development
Stage - IV hardening
Uses and Advantages of Plant Micropropagation
- All-The-Year-Round Propagation
2). Propagation of Difficult Species
3). Multiplication of superior clones and maintenance of uniformity.
(4). Eradication of diseases and Multiplication of disease free plants.
Limitations of Plant Micropropagation
- High investment cost.
- Requirement of more skill.
- High electricity consumption.
- Presence of traces of somaclonal variation.
- Possibility of loss of rare genetic material from contamination.
- Techniques of micropropagation are not available for many species.
- Vitrification may be a problem in some species.
somatic embryoids derived from plant tissue culture and encapsulated by a hydrogel.
ARTIFICIAL SEEDS
Isolated somatic embryoids are mixed with Sodium alginate and dropped into Calcium nitrate solution
Gel Complexation Method
Types Of Synthetic Seeds
-Uncoated desiccated somatic embryos e.g. orchard grass.
-Coated desiccated somatic embryos e.g. Carrot.
-Encapsulated coated hydrated somatic embryos eg. Alfalfa.
-Uncoated hydrated embryos (in a fluid drilling gel) e.g. Carrot.
Limitation of Artificial Seeds
-When the artificial seeds are stored at low temperature the embryos show a characteristic drop in conversion.
-Cost of production is high
In this pathway, groups of cells of the apical meristem in the shoot apex, axillary buds, root tips, and floral buds are stimulated to differentiate and grow into shoots and ultimately into complete plants.
Regeneration
It is a technique that uses young tissue to generate small masses of cells from which many new genetically identical plants may grow.
Somatic embryogenesis
