Inventions and Inventors Volume 1 - Online Public Access Catalog

422 / In vitro plant culture
plant physiologist at the National Institute for Agronomic Research
in France, was one of many scientists during this time who
had become interested in the formation of tumors in plants as well
as in studying various pathogens such as fungi and viruses that
cause plant disease.
To further these studies, Morel adapted existing techniques in order
to grow tissue from a wider variety of plant types in culture, and
he continued to try to identify factors that affected the normal
growth and development of plants. Morel was successful in culturing
tissue from ferns and was the first to culture monocot plants.
Monocots have certain features that distinguish them from the other
classes of seed-bearing plants, especially with respect to seed structure.
More important, the monocots include the economically important
species of grasses (the major plants of range and pasture)
and cereals.
For these cultures, Morel utilized a small piece of the growing tip
of a plant shoot (the shoot apex) as the starting tissue material. This
tissue was placed in a glass tube, supplied with a medium containing
specific nutrients, vitamins, and plant hormones, and allowed
to grow in the light. Under these conditions, the apex tissue grew
roots and buds and eventually developed into a complete plant.
Morel was able to generate whole plants from pieces of the shoot
apex that were only 100 to 250 micrometers in length.
Morel also investigated the growth of parasites such as fungi and
viruses in dual culture with host-plant tissue. Using results from
these studies and culture techniques that he had mastered, Morel
and his colleague Claude Martin regenerated virus-free plants from
tissue that had been taken from virally infected plants. Tissues from
certain tropical species, dahlias, and potato plants were used for the
original experiments, but after Morel adapted the methods for the
generation of virus-free orchids, plants that had previously been
difficult to propagate by any means, the true significance of his
work was recognized.
Morel was the first to recognize the potential of the in vitro culture
methods for the mass propagation of plants. He estimated that several
million plants could be obtained in one year from a single small
piece of shoot-apex tissue. Plants generated in this manner were
clonal (genetically identical organisms prepared from a single plant).