The First Book of Farming | Page 9

fuzz or mass of root hairs near the
ends of the tender roots of the seedlings (Fig. 13). Plant similar seed in
sand or soil, and when they have started to grow pull them up and
notice how difficult it is to remove all of the sand or dirt from the roots.
This is because the delicate root hairs cling so closely to the soil grains.
The root hairs are absorbing moisture laden with plant food from the
surface of the soil particles. The root hairs are found only near the root
tips. As the root grows older, its surface becomes tougher and harder,
and the hairs die, while new ones appear on the new growth just back
of the root tips, which are constantly reaching out after moisture and
food. The moisture gets into the root hairs by a process called osmose.
The following interesting experiment will give you an idea of this
process or force of osmose.
[Illustration: FIG. 10. A plow stopped in the furrow, to show what it
does to the roots of plants when used for after-cultivation. Notice the
point of the plow under the roots.]
[Illustration: FIG. 11. A corn-plant ten days after planting the seed. To
show how quickly the roots reach out into the soil. Some of the roots
were over 18 inches long.]
=Experiment.=--Procure a wide-mouthed bottle, an egg, a glass tube
about three inches long and a quarter-inch in diameter, a candle, and a

piece of wire a little longer than the tube. Remove a part of the shell
from the large end of the egg without breaking the skin beneath. This is
easily done by gently tapping the shell with the handle of a
pocket-knife until it is full of small cracks, and then, with the blade of
the knife, picking off the small pieces. In this way remove the shell
from the space about the size of a nickel. Remove the shell from the
small end of the egg over a space about as large as the end of the glass
tube. Next, from the lower end of the candle cut a piece about one-half
inch long. Bore a hole in this just the size of the glass tube. Now soften
one end of the piece of candle with the hole in it and stick it on to the
small end of the egg so that the hole in the candle comes over the hole
in the egg. Heat the wire, and with it solder the piece of candle more
firmly to the egg, making a water-tight joint. Place the glass tube in the
hole in the piece of candle, pushing it down till it touches the egg. Then,
with the heated wire, solder the tube firmly in place. Now run the wire
down the tube and break the skin of the egg just under the end of the
tube. Fill the bottle with water till it overflows, and set the egg on the
bottle, the large end in contact with the water (Fig. 14). In an hour or so
the contents of the egg will be seen rising in the glass tube. This
happens because the water is making its way by osmose into the egg
through the skin, which has no openings, so far as can be discovered. If
the bottle is kept supplied with water as fast as it is taken up by the egg,
almost the entire contents of the egg will be forced out of the tube. In
this way water in which plant food is dissolved enters the slender root
hairs and rises through the plant.
=Experiment.=--This process of osmose may also be shown as follows
(Fig. 15): Remove the shell from the large end of an egg without
breaking the skin, break a hole in the small end of the egg and empty
out the contents of the egg; rinse the shell with water. Fill a
wide-mouthed bottle with water colored with a few drops of red ink.
Fill the egg-shell partly full of clear water and set it on the bottle of
colored water. Colored water will gradually pass through the membrane
of the egg and color the water in the shell. Prepare another egg in the
same way, but put colored water in the shell and clear water in the
bottle. The colored water in the shell will pass through the skin and
color the water in the bottle. Sugar or salt may be used in place of the

red ink, and their presence after passing through the membrane may be
detected by taste.
CONDITIONS NECESSARY FOR ROOT GROWTH
We have learned some of the things that the roots do for plants and a
little about how the work is done. The next thing to find out is:
What conditions are