Plant tissue culturing techniques have become especially important in the
agricultural community over the past 10 years. During this time period, plant
tissue culture has effectively moved from the confines of small laboratories and
has taken its place among some of the more mainstream, broad-scale techniques
employed by the agriculture industry.
Plant tissue culture, more technically known as micropropagation, can be
broadly defined as a collection of methods used to grow large numbers of plant
cells, in vitro, in an aseptic and closely controlled environment. This technique
is effective because almost all plant cells are totipotent—each cell possesses the
genetic information and cellular machinery necessary to generate an entire
organism. Micropropagation, therefore, can be used to produce a large number of
plants that are genetically identical to a parent plant, as well as to one another.
|Figure 1 The basic steps of
The standard protocol for performing plant tissue culture experiments is
fairly basic. First, it is essential that a sterile environment be created. The
medium used to grow the plant tissue, the plant tissues themselves, and the
environment surrounding the tissue culture, must be free of all possible
contaminants. The presence of any bacterial, fungal, algal, or viral contaminants
could potentially rob the desired plants of the nutrients provided by the culture
medium and have devastating effects upon their growth. Once a sterile
environment has been established, tissue can be collected from the plant’s leaf,
shoot, bud, stem, or root (see Figure 1). Because each of these cells is totipotent,
each has the potential to express an entire organism. The tissue sample can
then be placed on an aseptic (free of microorganisms), nutrient-rich medium
where its cells will begin to grow and develop into the desired plant product.
The nature of the medium and the nutrients that it contains is dependent upon
the type of plant being grown and the properties that the grower wishes to
express. Finally, the developing tissue should be maintained in a closely
controlled chemical and physical environment, such as a greenhouse, to achieve
the best results.
The benefits of plant tissue culture are extensive in the agricultural world.
Micropropagation is more favorable than traditional crop breeding methods in
many respects, the first being that it allows for the production of huge numbers
of plants in a very short period of time. Plant tissue culture is also advantageous
to growers because an overwhelming number of plants can be produced
using the tissue collected from a single parent plant—a plant that itself remains
unharmed in the tissue harvesting process. Crop production through micropropagation
also eliminates the possibility of any interruption in the growing
season because it can be carried out inside the carefully regulated environment
of a greenhouse. Because the chemical and physical environment inside a
greenhouse can be closely monitored, any lull in production that might typically
occur as a result of seasonal change can be avoided.
Micropropagation will be crucial to the agriculture industry in the future
because it is used to produce plants that have been genetically modified and
selected for their ability to resist certain indigenous environmental stresses.
Currently, scientists and members of the agricultural community have joined
forces to investigate the possibility of creating lines of tomatoes that possess
increased salt tolerance (to be grown in areas in which the soil is high in
salinity), plants that are completely resistant to various viral, bacterial, algal,
and fungal infections, tobacco plants whose leaves can withstand freezing
temperatures, and crops that are entirely resistant to harmful and destructive