Personality of plants

LIFE OF A PLANT
called chlorophyll. It is the material which
gives leaves their green colour. It is one of
the most important substances in plantdom.
Under the influence of sunlight, this chlorophyll
takes the carbon dioxide of the air, and, with
water and certain minerals, makes starch, the
raw material of plant construction. This pro-
cess, called photosynthesis, goes on while the
sun shines, and stops with the approach of
darkness. The necessity of plenty of light can-
not be overestimated.
In the manufacture of starch, oxygen occurs
as a by-product. As the plant has no use for
this element, it is breathed out from the surface
of the leaves. From the standpoint of man,
this makes plants atmospheric purifiers. At
night, when the making of starch is suspended,
there is often a superabundance of carbon dioxide
within plant structures. It is this gas which
is now exhaled, though in very small amounts.
Some authorities maintain that the excess of
carbon dioxide is contained in water absorbed
by the roots. In the daytime this is welcomed
as additional starch material, but at night there
is no use for it.
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