Download Tissue Culture

• Mitosis is the type of cell division that
produces new cells for growth and to
replace old cells that are worn out,
damaged or dead. An application of
mitosis is in cloning and tissue culture.
• Tissue culture is the growth of tissues or
cells separate from the organism. This is
typically facilitated via use of a liquid,
semi-solid, or solid growth media, such as
broth or agar. Tissue culture commonly
refers to the culture of animal cells and
tissues, while the more specific term plant
tissue culture is used for plants.
• Plant tissue culture is a practice used to
propagate plants under sterile conditions,
often to produce clones of a plant.
ORIGIN OF PLANT TISSUE CULTURE
• Nature has been cloning organisms for
billions of years. For example, when a
strawberry plant sends out a runner (a
form of modified stem), a new plant grows
where the runner takes root. That new
plant is a clone. Similar cloning occurs in
grass, potatoes and onions.
• Scientists have been able to clone plants
by taking pieces of specialized roots,
breaking them up into root cells and
growing the root cells in a nutrient-rich
culture. In culture, the specialized cells
form calluses(undifferentiated mass of
tissue). The calluses can then be
stimulated with the appropriate plant
hormones to grow into new plants that are
identical to the original plant.
A piece of tissue called
explant is taken from the
parent plant and cut into
small pieces.
The pieces of tissues are
sterilised with dilute sodium
hypochlorite solution to
prevent the growth of
pathogens (bacteria and
fungus).
Each sterile tissue piece is
placed onto a growth
medium (gel containing
nutrients and growth
regulators).
The shoots are separated
and each is placed in nutrient
medium with rootstimulating hormones to
encourage rooting.
Callus is stimulated with
shoot-stimulating hormones
to form multiple shoots.
The tissue cells divide by
mitosis to produce a mass of
loosely arranged and
undifferentiated cells called
callus.
Once the roots grow, the
plantlets (little plants) are
planted in sterile compost to
grow.
DIAGRAM AND CHARTS OF PLANT
TISSUE CULTURE
Micropropagation using meristem and shoot culture to produce large
numbers of identical individuals.
Screening programmes of cells, rather than plants for advantageous
characters.
Large-scale growth of plant cells in liquid culture as a source of
secondary products.
Crossing distantly related species by protoplast fusion and
regeneration of the novel hybrid.
Production of dihaploid plants from haploid cultures to achieve
homozygous lines more rapidly in breeding programmes.
As a tissue for transformation, followed by either short-term testing
of genetic constructs or regeneration of transgenic plants.
Removal of viruses by propagation from meristematic tissues.
The production of exact
copies of plants that produce
particularly good flowers,
fruits or have other desirable
traits.
To quickly produce mature
plants.
The production of multiples
of plants in the absence of
seeds or necessary
pollinators to produce seeds.
The regeneration of whole
plants from plant cells that
have been genetically
modified.
The production of plants in
sterile containers that allows
them to be moved with
greatly reduced chances of
transmitting diseases, pests,
and pathogens.
The production of plants
from seeds that otherwise
have very low chances of
germinating and growing
such as orchids and
nepenthes.
To clean particular plant of
viral and other infections and
to quickly multiply these
plants as 'cleaned stock' for
horticulture and agriculture.
Decreases genetic
variation and
limits biodiversity.
It is very
expensive and
time consuming.
An infected plant
sample can
produce infected
progeny.
Not all plants can
be successfully
tissue cultured,
often because the
proper medium
for growth is not
known or the
plants produce
secondary
metabolic
chemicals that
stunt or kill the
explant.
Sometimes plants
or cultivars do not
come true to type
after being tissue
cultured.
Infection may
continue through
generations if
precautions are
not taken.