  
Plants' Cooling Systems
 A
plant and a piece of stone in the same place do not warm up
to the same degree, even though they receive the same amount
of solar energy. Every living creature will experience negative
effects if it stays out in the sun. So what is it that enables
plants to be minimally affected by the heat? How do plants
manage this? Why does nothing happen to plants even in great
heat, even when its leaves burn in the sunshine all through
a hot summer?
Apart from their own internal warming, plants
also take in heat from the outside and maintain the temperature
balance in the world. And they themselves are exposed to this
heat while carrying out this heat-retention process. So, instead
of being affected by the ever-increasing temperature, how
is it that plants can continue to take heat in from outside?
Considering that plants are constantly under
the sun, it is natural that they should need more water than
other living things. Plants also constantly lose water by
the perspiration on their leaves. In order to prevent such
water loss, the leaves, the surface of which are always turned
towards the sun, are generally covered in a waterproof protective
wax known as the cuticle. In this way water loss on the upper
surfaces of leaves is prevented.
But what about the under surfaces? Because the
plant loses water from there, the pores whose function is
to enable the diffusion of gases are generally on the bottom
surfaces. The opening and closing of the pores regulates the
plant's taking in enough carbon-dioxide and giving off enough
oxygen, but not in such a way as to lead to water loss.
In addition to this, plants disperse heat in
different ways. There are two important heat dispersal mechanisms
in plants. By means of one of these, if the temperature of
a leaf is higher than that around it, air circulates from
the leaf towards the outside. Air changes stemming from heat
distribution lead to the air rising, because hot air is less
dense than cold. For this reason the hot air on the surface
of the leaf rises, leaving the surface. Because cold air is
denser, it descends to the surface of the leaf. In this way
heat is reduced and the leaf is cooled down. This process
goes on for as long as the temperature on the surface of the
leaf is greater than that outside. In very dry environments,
such as deserts, this situation never changes.
By means of the other heat dispersal system of
plants, leaves can perspire by giving off water vapor. By
virtue of this perspiration, the evaporation of water permits
the plant to cool down.
These dispersal systems have been designed to suit the conditions
where the plant lives. Every plant possesses the systems it
needs.
This activity of plants could be described as
a kind of water engineering. The trees in a thousand square
meter area of forest can comfortably put 7.5 tons of water
into the atmosphere. Trees are like giant water pumps, passing
the water in the soil through their bodies and sending it
into the atmosphere. This is a most important task. If they
did not possess such a feature, the water cycle on the Earth
would not happen as it does today, which would mean the destruction
of the balances in the world.
Although their stems are covered with a wooden,
dry substance, plants can pass tons of water through their
bodies. They take this water from the soil, and after using
it in various parts of the high technology factories in their
bodies, give it back to nature as purified water. At the same
time that they do this, they also separate part of their intake
of water with the aim of using the hydrogen in the nutrition
production process.
What we have described as the perspiration in
leaves or the moisture in the areas where the trees live,
actually occur as the result of activities which are essential
to the survival of life on the planet.
What we see in these processes of plants is a system of such
perfection that it would run down and stop working if even
one part of it were taken away. There is no doubt that it
was God, the Compassionate and the Merciful, Who is aware
of all creation, Who designed this system and flawlessly installed
it in plants.
He is God - the Creator, the Maker, the
Giver of Form. To Him belong the Most Beautiful Names. Everything
in the heavens and earth glorifies Him. He is the Almighty,
the All-Wise. (Qur'an, 59:24)
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