Evening star. [volume] (Washington, D.C.) 1854-1972, 1938-05-12
STARS, MEN AND ATOMS
Notebook Of Science Progress in Field.
laboratory and Study,
BY THOMAS K. HENRY.s

There is some still unidentified sub
stance in plants that causes roots to
grow.
This growth hormone. which may
prove to be one of the most important
chemicals in nature, has been named
rhizocaline by DR.. William c. Cooper.
Department of Agriculture scientist,
whose experiments have just demon
strated its existence.
For some time past it has been known
that the ends OF cuttings could be made
to root much quicker and stronger by
dipping them in various solutions. These
chemicals themselves have been cred
tied with promoting the root growth.
One OF them, which actually was used
by DR.. Cooper, is indole-acetic acid
He dipped the ends of a large num-
Der of slips from lemon tree in a solu-
ton Of this acid and then stuck half of
them in the ground. AS was to be ex-
pected, he got much quicker and more
vigorous root growth than from I'M
treated cuttings of the same tree. The
other half he did not plant, but after q
few days cut of the treated portions and
again soaked the cut ends in indole-
acetic acid
Again there was a response when
these ends were placed in the ground,
but 1t was not nearly so vigorous a.
had been the case with the earlier plant
lngs. AS he interprets the results, the
still unknown root-growth hormone is
distributed throughout the plant. It
tends to How slowly towards a cut end,
making possible the formation of new
roots and consequently new plant. The
only function OF the indole-acetic acid
or any of the other applied growth"
substances, is to hasten this flow so that
a greater concentration of the mysterious
substance is brought about.
In the case Of the lemon cutting ex-
perlments, DR.. Cooper believes, the first
soaking had drawn down a large part
OF the substance present in the plant
fragment. There wasn't much left to
be drawn down by the second applica-
ton.
A 20-hour treatment of lemon cut
tings, he says, apparently drew down
ABOUT two-thirds Of this substance-or
substances for there may be two or
three-and conceptrated it in the base.
IN 4o hours the rhizocaline movement
was practically complete. If the treated
base was cut off after 20 hours there
was still enough left to produce. some
root formation. After 40 hours no roots
could be started when the base was
cut off.
Dr. Coopers experiments with various
other plants indicate that those which
DO not root readily when treated-sone
apple cuttings, for example-are lacking
in rhizocaline.
Bug armies are on the march early
this year. An early spring has brought
them from their winter retreats all over
the country. The vanguard, consisting
OF worms and caterpillars, have BROUGHT
widespread destruction to crops in the
South, according to reports reaching the
Department Of Agriculture.
Oats and alfalfa in Louisiana, Missis-
sippi and Arkansas have been badly in
jured by army worms and cutworms.
The tomato worm has appeared in the
fields Of Florida. A serious threat is the
unusual winter survival of the corn-ear
worm. It is present In greater numbers
than last year in New Jersey, Virginia,
Ohio and Texas and for the first time
on record 1t lived through the winter in
Kansas and Utah.
The eastern tent caterpillar is out In
large numbers and has started to skele-
tonize foliage from New Hampshire to
South Carolina. The forest tent cater
pillar, also out In unusual numbers, II
doing tbs sams In 1hs woodlands Of