Evening star., 1952-02-08
unsupported Factor
In Heredity Indicated
Neutrons Seen Transmitting
Elements in Germ PIusm

S0tOlS SGGH ttMstSsHuttWS
Elements in Germ Plusm
By Thomas R. Henry
Far-reaching changes In plant growth
result from what Is believed TO be trans
mutation Of elements In germ plasn.
This may constitute . hitherto un-
suspected factor In heredity. which has
played significant part In evolution.
The significance Of the possible transs
mutation factor Is brought out In ex-
perimentS with the bombardment Of
corn seeds with slow neutrons the same
enthusiastically minute particles used
Ia the fiSSion Of uranium lin the atomic
pile at the Atomic Energy Commissions
Argonne Laboratory at the University
OF Chicago. This research, under COM
mission fellowship. has just been re-
ported In the Journal Of Heredity here
by Drs. John w. Schmidt and E. r.
Frplik Of the Nebraska Agricultural Ex-
pertinent Station.
Both seeds and pollen were subjected
TO this heavy bombardment Of ap-
proximately 70 billion neutrons per
square centimeter per second. The
changes In plant growth from the seed
bombardment were about II times
greater than the treatment Of pollen In
the same way. Most Of the results were
detrimental to the resulting plants, a.
Is always the case.
The seed bombardment resulted In
shorter corn stalks, narrower leaves,
One-Sided leaf development, mottling
and wrinkling Of the leaves. and q darker
than normal bluish-green color. Bonn
bardment Of pollen used In artificial
fertilization resulted only in shorter
stalks and q considerably decreased
plant stand.
Greater Than With X-Rays.
Both seed and pollen were also treated
with X-rays, the now classic means Of
changing heredity, Of approximately the
same theoretical potency as the neu-
irons. The effects Of the neutron bonn.
bardment, especially on the seeds. was
considerably greater.
Now It is known that the effects Of
X-rays on germ plasm are due to ioni2a-
tion. the stripping Of outer electronS
from atoms and thus changing chemical
reactions. Neutrons. presumably. do the
same, but their increased effectiveness. it
Is stressed, indicates that something else
Is happening.
One possibility is that some Of the
nitrogen in seed is transmitted into
carbon through capture Of neutrons by
the nuclei Of nitrogen atoms. This proc.
ess goes on constantly in the upper
reaches of the earth's atmosphere. The
nitrogen is transmitted into radioactive
carbon. Another possible significant
transmutation in the seed results from
the transmutation Of extremely minute
amounts Of boron into lithium.
First made experimentally possible IN
the atomic pile, these same processes
going on all over the earth since life
began, due to cosrnic ray bombardment
from outer space and the effects Of trans
mutations in plant and animal germ
plasm, can only be conjectured.
s, Another factor is that the forms OF
elements produced by transmutation are
themselves radioactive and, If they hap
pen to be Short-lived, act as miniature
atomic bombs within the germ plasm
itself. The greater effects produced on
seed than on pollen, the male factor OF
plant germ plasm, can be explained as
, due to the greater area exposed.
@ Gamma Ray Treatment Studied.
Effects Of gamma rays, similar to
X-rays but somewhat more penetrating
and powerful, on corn seed and pollen
are being studied in a massive expert
mefit at the Brookhaven Il. - station
Of the Atomic Energy Commission and
have just been described in report by
DR.. w. Ralph Singleton. '.'
For the past two years, corn plants
have been grown in concentric circles
around bar Of radioactive cobalt which
is sending out radiation continuously ex-
cept when it is necessary for attendants
to go into the field for few seconds
at time. Then it is lowered into the
ground by remote control.
A total Of 275,000 seeds produced by
this radiated corn have been examined
to date. The intensity Of the radiation
received by the plants fell OF directly
with the distance from the cobalt bar.
No results could be found at distances
beyond 10 meters. At the highest radia-
tion, ] per cent Of $500 seeds showed
changes which presumably would be re-
hected in changed characters Of the
seeds grown from them.
Pollen from the radiated plants Is
being used to fertilize normal plants
and direct increase of mutations with
the dosage received has been found,
DR.. Singleton reports.
The work, it is stressed, may have
considerable practical Importance in
plant breeding work. theoretically, 1t
should be possible to detect hereditary
changes which will be permanent in two
or three years, much shorter time
than is required in present breeding
teehniqueS.
While similar effects might be postu-
lated for animal germ plaSm, controlled
experiments would be practically impos-
sible, and the basic data must be OBJ
tanned from plants which stay put"
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