In 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
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 ROOT END
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
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
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
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
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.
| BİTKİLERİN KULLANDIĞI
||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
|| in proteinlerin coenzymes
||Affectts the cytosketeleton,membranes, and many
enzymes: second messenger
||In cholorophyli: required by many
enzymes: stabilizes ribosomes
||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
||Enzyme activation; auxin Synthesis
||In active site of many redox enzymes and electron
||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 elements.
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.
Milani, Bradshaw, Biological Science, A molecular Approach, D.C.Heath
and Company, Toronto, p.430
Malcolm Wilkins, Plantwatching, New York, Facts on File Publications,