ROOTS : NATURE'S DRILLERS
order to survive, plants need to carry out photosynthesis, and for that
they need the water and minerals they take from the soil. To meet these
needs, they require the roots which drill under the ground. The job of
the roots is to spread rapidly underground like a net and draw up water
and minerals. As well as this, plant roots, despite their delicate structure,
enable plants which can weigh up to tons to hold on to and fix themselves
in the soil. The soil-gripping nature of roots is most important, because
it prevents landslides and the fertile upper layers of soil being washed
away by the rain, and other unwanted occurrences that can adversely affect
Roots need no equipment for all this. They have no engine to provide
the power to start the process of water-drawing. Neither is there any
equipment to pump the water and minerals to the stem, metres away. But
roots can spread over a wide area and draw water. So, how do they do it?
How Does This System Work?
A typical red maple tree growing in a humid climate may lose as much
as 200 liters of water per day. This represents a serious loss for the
tree. This water needs to be replaced immediately if the plant is to
survive. Thanks to the flawless root system plants have, every drop
of water which evaporates is replaced.31
The roots, which spread down into the depths of the earth, send the water
and minerals which the plant needs right up to the leaves, through the
stem and branches. The roots' drawing of water from under the ground closely
resembles a drilling technique. The ends of the roots keep looking for
water in the depths of the soil until they find it. Water enters the root
through an external membrane and capillary cells. It then passes through
the cells to the stem tissue. From there it is transported to every part
of the plant.
This process which the plant carries out so perfectly is, in fact, a
very complicated one. So much so that the secret of the system is still
not completely known, even in these days of space-age technology. The
existence of this sort of "pressure tank" system was discovered in trees
some 200 years ago. Yet no law has yet been discovered to definitively
explain how this movement of water, against gravity, actually comes about.
All that scientists have been able to do on this subject is put forward
a number of theories about certain mechanisms. Those which have been demonstrated
in experiments are thought of as valid to some extent. The outcome of
all these scientists' efforts is the recognition of the perfection of
the pressure tank system. Such a technology, packed into a tiny space,
is just one of the proofs of the incomparable intelligence of the designer
of the system. The water transport system in trees, and everything else
in the universe, were created by God.
The Water Transport System
The Pressure System in Plant Roots
When the internal pressure in root cells is lower than the outside pressure,
plants take in water from outside. Another way of putting it is that they
take water from outside only when they need it. The most important factor
establishing this is the amount of pressure produced by the water in the
roots. This pressure has to be balanced with that outside. For this to
happen, the plant needs to take in water from the outside when the amount
of internal pressure falls. When the opposite happens, when the inside
pressure is higher than the outside, the plant gives off water from inside
itself by means of its leaves to re-establish the balance.
| THE GENERAL STRUCTRE OF THE
On the left page can be seen a detailed plan of
all the elements in a plant's transport system. The roots carry
the water they absorb from the soil to the steele, where it enters
the vascular system in the stem. Through the vascular system, water
and nutrients make a trip upward for metres in the stem, tirelessly,
right up to the farthest leaves. The system, which starts at the
roots and goes as far as the leaves is unarguably the product of
a most superior planning. This planning belongs without doubt to
God, the Creator of everything.
The picture to the side shows the general structure
of a growing root tip and a close up of the root hairs which lie
just behind the tip.
If the level of the water in the soil were slightly higher than normal,
the plant would continually take in water, because the external pressure
was higher, and this would eventually damage it. If it were a little lower,
on the other hand, the plant cell could never take in water from the outside
because the external pressure would be low. It would even have to give
off water to maintain the pressure balance. In either case the plant would
dry up and die.
This shows to us that plant roots contain a balance-control mechanism
to enable them to regulate the level of pressure needed at a precise moment,
neither more nor less.
How Roots Take in Ions from the Soil
The cells in the roots of a plant select particular ions
from the soil to use in cell reactions. Plant cells can easily take these
ions inside themselves, despite the internal concentration of some ions
in the plant being a thousand times greater than that in the soil solution.
So, this is a most important process.32
Let us imagine that the
minerals in the picture were put in front of us and we were
asked to choose which of them were necessary for our bodies.
It is impossible for anybody who has not had special training
to do this. Whereas plants have been selecting and using only
those elements they need from all those in the soil for millions
of years. Of course it is God, their Creator, who makes it
possible for plants to carry out this process, which for human
beings is impossible.
Under normal conditions, a transfer of materials will occur from an area
with a higher concentration to one with a lower concentration. But as
we have seen, just the opposite takes place in the roots' absorbing ions
from the soil. For this reason the process requires quite substantial
amounts of energy.
Two factors influence the passage of the ions through the cell membrane:
the membrane's permeability and the concentration of the ions on either
side of the membrane.
Let us examine these two factors by asking some questions about them.
What does a plant's choosing the required elements from those in the soil
actually mean? Let us first take the concept of "requirements." A root
cell has to know all the elements in the plant, one by one, to meet its
requirements. It has to establish which of all the elements it knows are
lacking in all parts of the plant and identify them as needs. Let us ask
another question. How is an element known? If the soil is not in a pure
state, in other words if there are other elements mixed up in it, what
has to be done to distinguish one element from all the rest?
Will it be possible for someone to tell which is which if elements such
as iron, calcium, magnesium, and phosphorus are put in front of him all
mixed up? How can he tell them apart? If he has received training in the
subject, he may be able to identify some of them. It will be impossible
for him to identify the rest, however. So how do plants make the distinction?
Or rather, how is it possible for a plant to know elements by itself,
and to find those ones most useful for it? Is it possible that such a
process should have been carried out in the right way every time for millions
of years by chance? In order to think about all of these questions-to
which the answer is "Impossible!"-in a more detailed and deeper way, let
us examine what kind of selective property roots possess and what happens
at the time of selection.
Let us review our chemical knowledge regarding the elements and minerals
which appear in many forms in nature. Where are they found? Which substances
go into which groups? What differences are there between them? What experiments
or observations are required to understand what each one is? Can the fastest
results be arrived at by chemical or physical methods in these experiments?
If we just look at things from the physics point of view can we make a
proper classification of these substances if they are put on a table in
front of us? Can we distinguish minerals by their colour or form?
We could go on. And the answer to all of the above questions is more
or less the same. Unless someone is an expert in the field, partial or
inadequate knowledge left over from school or university will not lead
a person to an accurate solution. In order to classify our knowledge of
minerals, let us this time take examples from the human body.
There is a total of three kilograms of minerals in our bodies. Parts
of them are essential for our health, and they are all present in the
necessary quantities. For example, if we had no calcium in our bodies,
our teeth and bones would lose their hardness. If there were no iron,
oxygen could not reach our tissues, because we would have no haemoglobin.
If we had no potassium and sodium, our cells would lose their electrical
charges and we would rapidly age.
Minerals are present in the soil in the same way as in the human body.
Their quantities, functions, and the forms in which they are found in
the soil are all different, and many living things make use of these minerals.
In plants, for instance, systems have been set up so that they can easily
take the elements they need from the soil. There being different fields
of use for them in their structures, all the elements have to go to different
parts of the plant after they are absorbed. They all have different tasks.
In order to live healthily, a plant needs such basic elements as nitrogen,
phosphorus, potassium, calcium, magnesium and sulphur. While plants can
take most of these substances directly from the soil, the situation is
different with nitrogen. Nitrogen makes up almost 80% of the atmosphere
by volume, however, it cannot be obtained or "fixed" directly from the
atmosphere by green plants. The plants meet their nitrogen need by absorbing
from the soil the nitrates processed by the soil bacteria.
| ELEMENTS REQUIRED BY
||In all organic molecules
||In most organic molecules
||In most organic molecules
||In proteins, nucleic acids, etc.
||İn nücleic acids, ATP, phospholipids, etc.
||Enzyme activation: water blance, ion blance
|| in proteinlerin coenzymes
||Affectts the cytosketeleton,membranes, and many enzymes:
||In cholorophyli: required by many enzymes:
||In active site of many redox enzymes and electron carriers:
needed for chlorophyli synthesis
||Photosynthesis: ion blance
||Activates many enzymes
||May be needed for carbohydrate transport (poorly understood)
||Enzyme activation; auxin Synthesis
||In active site of many redox enzymes and electron carrieers
||Nitrogen fixation: nitrate reduction
This table shows the elements
plants need, where plants take these elements from, and how they
are used. Plants only take and use the 16 elements they need from
among all those present in the soil. These processes, which even
people who study them find hard to understand, are carried out by
plants, thanks to the inspiration of God.
Other elements, too, are necessary for healthy development. But these
are needed in quite small quantities. This group includes iron, chlorine,
copper, manganese, zinc, molybdenum, and boron.
In addition to these 13 minerals, plants also need the three basic building
blocks of oxygen, hydrogen, and carbon, and get them from the carbon-dioxide,
oxygen, and water in the atmosphere. All plants need this total of 16
The most important factor contributing to the carbon and nitrogen
cycle in the environment, as outlined in the above picture, is without
doubt plant life. The nitrogen in the air cannot be taken in directly
by people and animals. When the nitrogen is passed to the soil, the
ammonia released is then oxidized by soil bacteria to nitrates, and
in this form it can be reabsorbed by plant roots. People and animals
then meet their nitrogen needs by eating the plants.
If these elements are taken in in too great or too small quantities,
various deficiencies arise in the plant.
For example, too much nitrogen from the soil leads to brittle growth
especially under high temperatures and succulent growth, while too little
can lead to yellowing, red and purple patches, reduced lateral bud, and
older growth. Phosphorus deficiency causes reduced growth, browning or
purpling in foliage in some plants, thin stems, reduced lateral bud breaks,
loss of lower leaves and reduced flowering. Phosphorus is a very important
element for the growth of young plants and seed production. In short,
the existence of these ions and their being taken in from the soil in
the required quantities are essential for healthy plant growth.33
What would happen if plants did not possess this ion-selection mechanism?
What would happen if plants took in all kinds of minerals, not just the
ones they need, or took in too many or too few minerals? There is no doubt
that in that event there would be serious disruptions to the perfect balance
in the world.