Evening star. [volume] (Washington, D.C.) 1854-1972, 1954-03-10
Several Antibiotics
Promote Plant Growth
Scientists Unable to Predict
Value to Agriculture
By Thomas r. Henry

A remarkable stimulating effect of
q few NEUTRALITY-SUSPICIOUS. to combat
human and animal disease germs-on
plant growth has just been reported
to the American Chemical Society
here.
It already. has been demonstrated
that minute amounts of certain anti
bl6ticS added to poultry and livestock
feed cause notable growth changes. but
the possible effect on plants has been
much more debatable.
The present experiments are reported
by Drs. Louis G. Nickel and Alexander
c. Finley Of the research laboratories
Of Charles Pfizer & Co. Of Brooklyn.
They were carried out with an expert
mental plant. duckweed, under strictly
laboratory conditions. It is still quite
uncertain whether they would hold
good for any field crop and the two
chemists are unable to offer any ex-
PLANTATION.
The majority Of the 20 antibiotics
tested on the plants raised in organic
solutions actually depressed growth.
Different Effects.
Far different was the outcome with
the nti-tuberculosis drug, isonicotinic
hydrazide, Penicillin G, the new sub
stance, thiolutin, and chloromycetin.
Each, according to the report publish
ed in the Journal of Agricultural and
Food Chemistry issued by the society.
had quite different specific effect.
Chloromycetin in concentrations Of
one part per million in the liquid solu-
ton in which the plants were grown.
for example, resulted in a 40 per cent
increase in growth in three weeks. At
concentration of 20 parts per million,
however, there was loss Of rs per
cent in the same period.
The anti-tuberculosis drug at one
part per million concentration caused
a growth increase of so per cent in
three weeks. A concentration of five
parts per million resulted in 70 per
cent increase, and at 20 parts per mil
lion there was a gain of las per cent.
When the duckweed was grown for six
weeks there was gain of 100 per cent
wet weight at concentration Of FIVE
parts per million, and of 270 per cent
when the concentration was increased
to 20 parts per million.
Most remarkable were the results
with penicillin. At concentration Of
20 parts per million in three weeks the
net weight Of the duckweed had in
creased more than threefold over nor
NAL and in six weeks more than five.
fold
Value Unpredictable.
Duckweed, Of course, is not an
agricultural crop. The growth rate in
creases were obtained under strictly
comfortable laboratory conditions. For
this reason. the two chemists stress.
they cannot predict that antibiotics
ever will have a practical value in the
field, but the experiments are likely to
throw new light on the fundamental
nature Of plant growth.
There is a possibility. they say, that
normally plant growth is slowed down
by certain poisons produced and ex-
creted by the plant itself in the growth
process. Thus an automatic brake is
placed on growth. If this is the case,
the antibiotics may nullify the effect
Of these poisons. Another possibility
Is that the substances cause an increase
in the permeability. of plant tissue so
that there is greater water uptake.
Still another, theory is that the anti
biotics increase the rate of synthesis
OF vitamins essential to plant growth.
A different explanation, they stress,
may be necessary for the action Of
each antibiotic. This has already been
demonstrated in animal feeding.