Mountain Home maverick. [volume] (Mountain Home, Idaho) 1906-1911, 1907-04-25


with the kinds not used because no
more of them can come in: but of
the kinds which it uses, more con-
tinues to arrive as fast as the plant
picks out these materials for its
own substance. Removal of these
food particles by placing them in
the tissue, reduces the relative
saturation of that substance in the
current, and more of it comes in
from the root to supply the place of
| the food removed, causing an up
| ward flow, the force exerted by
which we then term root pressure. I
We may demonstrate this upward
root pressure by cutting off the
stem of vigorous, growing sum
flower, just above the ground, and
tby fitting over it first a rubber and (
Before many hours the ascending
sap will cause the water to rise in
the tube. The common nettle Will
thus sustain column of water 10
| feet high. The sap goes upward,
mot between thesbark and the wood,
| as commonly supposed, but through
the young wood. A piece off corn
stalk or celery put into IA colored
solution, and cut off after few
! hours, shows. the <colqr ing. matter
/ in dots corresponding with the
! stringy parts of tough, celery and
! with the small wood bundles of
the corn. Stalk. It is root pressure
4 from below, and the osmotic force
due to evaporation above, that cause
the sap to ascend through these
| woody bundles, which, as veins and
veinlets, reach to all parts of the
leaf surface.
i Quite as wonderful, in. fact, as
the work of the roots and stems,
and much more impressive as 10 its
visible results, the work of the
leaves next claims our attention.
The plant must breathe; and, like
the animal, 1t must breathe oxygen.
1t does so chiefly by means of the
!. caves which are its lungs: Oxygen
;s constantly absorbed by the &C.
icate parts of plant foliage, and
even by the roots and the seeds,
but especially by the stornata of
, the leaves. Stonata, Or breathing
pores, are small openings in the
epidermis of leaves and soft Stems,
to allow the passage of air and other
gases. Two guard cells open or
close the gate to the stemata as the
conditions of the atmosphere may
require. The pores are usually
most numerous on the under side of
/ the leaves. Their number to the
square inch varies from 200 on the
leaf of mistletoe to 100, 600 on the
, leaf of a lilac, SO that they are very
small. AS the air enters, the oxy-
gen passes into the leaf cells, and
} unites with carbon there, forming
cal bon dioxid, which is then ex-
hailed, in manner resembling the
respiration of animals. A growing
plant may absorb an amount of oxy-
gen equal TO it's bulk in "a hours.
But carbon dioxid is likewise
| 'breathed' in by the leaves; and
whenever these have green co1oring
matter (chlorophylD present and
the sun is shining, the carbon of
this gas unites with watery sub
stances in the leaf and forms
starch, while the oxygen is thrown
off. This process, by means of
) which the plant is chiefly built up,
| since plants consist mainly of car
bon, is the main form of plant di-
, gestion and assimilation. During
the day, when this process is more
, or less active, much oxygen may be
given off; during the night, when
this process ceases, the effect of
/ respiration is to give off small
quantities of carbon dioxid. The
starch formed in the leaves during
the daytime is changed into the
) roots, tubers, or stem, or stored in
: the thickened leaves for future
: growth.
A third process carried on by
the leaves is Transportation, the
: means by which the plant gets rid
= Of its surplus water. The plant
a absorbs. water in much greater
S Quantity than it needs, in order &c
e secure. the proper amount of dis
oil solved food substance. This water
. evaporates from the Surfaces OF
= Eleaves and green stems. Thousands
d. of minute pores aid this process
e also; and these stomata open il
n moist and close in dry weather, tc
e regulate the amount of transpira.
S ton.
n The work of the flowers in secur.
It ing cross-fertilization and of the
E seeds in getting disseminated anc