The Ordway new era., 1922-02-24

| was set on q Snel1 outside tne green
house and single branch run through
the glass into the warm interior. When
spring came 1t was the interior brancf
that remained dormant, all the out
side branches putting out leave:
promptly. Thus the two experiments
served to check each other.
From a comparison of these two
experiments 1t is evident that the diff
ference in behavior of the indoor and
| outdoor branches could not have been
caused by any special action of the
root system, for In one experiment the
roots were inside, and in the other,
out. 1t Is clear that the causes that
| stimulated growth in the exposed
stems operated in the stem itself, not
In the roots. The theory is that the
cold weakens the plant cells, and by
destruction In part turns the starch
to sugar, thus assuring new growth.
This event, it Is asserted, cannot take
place If the plants are protected from
frost and cellular injury.
A little consideration will show how
important the principle Of chilling is
to those species of trees and shrubs
which are subjected each year to sew
eral months of freezing weather. If
they are so constituted as to start in
to growth as easily in the warm days
of late fall as they do In the warm
days of early spring, many species
would come into flowers and leaf in
those warm autumn spells that we
call Indian summer. and the stored
food that the plant required for its
normal vigorous growth in the follow
Ing spring would be wasted in a
burst of new autumn growth, which
would be killed by the first heavy
freezes and would be followed by a
winter Of weakness and probable
death.
But when two or three months of
chilling are necessary before new
ly dormant plant will respond to the
usual effect of warmth. such plants
are protected against the dangers of
growth in Indian summer. 1t is prob
able that all our native trees and
shrubs are thus protected.
Anyone may make a simple and in
structive experiment in the fall and
winter with such early spring bloom
ers as alder, hazelnut, pussy willow,
yellow bush jasmine, forsythia, JAP
anese ounce, peach and plum. In
mid-autumn bring into your living
room and set In water freshly cut,
dormant, leafless branches of these
plants. They will not bloom. At in
tervals of few weeks during the late
autumn and winter try the same eX-
pertinent again. 1t will be found that
the branches cut at later dates will
come into bloom under this treatment.
They will not do so, however, until
the expiration of the period chilling
appropriate to the various kinds Of
plants included in the experiment.
1t might be argued that in the trop-
les there is no chilling weather, yet
that trees and shrubs spring into
growth after the dormant period of
the dry season just as they do in tenn
perate climes after the dormant period
of winter. The critical scientific man
will therefore ask, Are there not 9TH
er agencies than chilling which will
start dormant trees and shrubs Into
growth even in our own latitude?" 1t
must be said in reply that there are.
And it is worth while to consider some
OF these causes, for not only are they
of interest in themselves but also, in
stead of weakening the hypothesis
here presented. they serve to strength
en- and confirm it.
The pruning of long-dormant plant