P. Abelson


 PLANT BIOTECHNOLOGY

 Technology has been applied to agriculture and the preparation and
preservation of food for a long time. Great improvements in yield and
quality have occurred. In many respects, in the short-term, the new tech-
nologies will enhance rather than supplant the old. For example, conven-
tional methods of plant selection, breeding, and field testing will not be
abandoned. In comparison to our knowledge about human physiology and
biochemistry, we are ignorant about the plant world. We are especially
lacking in knowledge about the role of the microbial life that exists in the
soil surrounding the roots of plants. We talk about altering the biochemis-
try of plants, but until recently have known little of the complex interac-
tions that control how genes are turned off or turned on.


TISSUE CULTURE

 The big recent development in plant biology is tissue culture. It is per-
mitting the cloning of selected and virus-free plants. It permits more rapid
improvement of many plants than could otherwise be achieved. Originally
only a few dicotyledonous plants could be propagated in tissue culture, but
the number is increasing rapidly. Culture of monocotyledonous plants
from single cells has not proceeded well, but Winston Brill of Agracetus
believes that eventually all plants will be propagated through tissue cul-
ture. Such an achievement would open the road to large-scale enhance-
ment of the capabilities of plants.
 Tissue culture is a necessary step in manipulations designed to select or
achieve an improved plant. By exposing tissue cultures to adverse condi-
tions such as salinity or pesticides, one can select those specimens most
capable of meeting the adverse condition.


GENETIC ENGINEERING OF PLANTS

 Tissue culture also is involved in the introduction of DNA into cells to
change their genetic inheritance. Calgene has succeeded in introducing a
gene that gives tobacco some resistance to the herbicide glyphosate. Gly-
phosate, also known under the trade name "Round-up," is a successful
product of Monsanto. The chemical blocks a pathway in plants in the
synthesis of aromatic amino acids. The gene that Calgene has introduced