has a number of commercial applications. These include:
i) Screening cells rather than plants for advantageous
characters, e.g. herbicide resistance/tolerance.
ii) Large-scale growth of plant cells in liquid culture inside
bioreactors as a source of secondary products, like
recombinant proteins used as biopharmaceuticals.
iii) To cross distantly related species by protoplast fusion
and regeneration of the novel hybrid.
iv) Embryo rescue (the resulting embryo as a result of
cross-pollination which would otherwise normally die is
cultured in a medium to rescue it).
v) For production of doubled monoploid plants from
haploid cultures to achieve homozygous lines more
rapidly in breeding programmes, usually by treatment
with colchicine which causes doubling of the chromosome
number.
vi) As a tissue for transformation, followed by either shortterm
testing of genetic constructs or regeneration of
transgenic plants.
vi) In vitro conservation of germplasm. This technique is
mainly used to conserve plant which do not produce
seeds or which have recalcitrant seeds which cannot be
stored under normal storage conditions in seed gene
banks. Hence, vegetatively propagated crops such as
root and tubers, ornamentals, medicinal plants and many
other tropical fruits have to be conserved using in vitro
methods.