Roots are essential for a plant. They anchor the plant to the ground absorb water and nutrients from the soil and deliver them to the rest of the plant. They also perform an important function that is not visible from the outside.
They also create a unique ecosystem that can have a profound
impact on the way plants grow. This feature is known to few. The outer
part of the root and the soil surrounding it is called the root zone. This zone
is home to a variety of microorganisms. Some of them are beneficial, some are
harmful, and some are not. Scientists are interested in ensuring that the
beneficial organisms gain the majority.
Soil modification
Soil modification can be created by changing the land
cultivation method. For example, if the garbage left in the field after the
harvest is favourable for the growth of bad microorganisms, the garbage can be
burned to destroy those microorganisms.
If pesticides are
mixed with the soil, they will eat the microorganisms, but the microorganisms
will quickly develop the ability to cope with the toxins. In addition,
pesticides can damage the environment and cause unwanted side effects. Instead,
introducing beneficial microbes into the roots and soil, and genetically
modifying bad microbes to make them good microbes, are new and exciting
alternatives.
Root zone
The root zone is the area that extends from the outer tissues
of the roots to the minerals in the soil. There are many different types of
microbes in this zone. They take the nutrients they need from the roots and the
substances they produce.
In return, they produce other substances that regulate the
growth of the plant. Scientists divide the root zone into three parts. Some of
the closest interactions between microbes and plants occur in the upper part of
the root.
This is called the root zone. The area from there to the soil
is the outer root zone. The area inside the root zone, where the microbes have
settled inside the root, is the inner root zone.
The root system determines how much a plant will produce. The
root system absorbs the water and nutrients needed for photosynthesis. Some of
the carbon compounds produced during photosynthesis are returned to the soil
through the roots. This is called root exudates.
These carbon compounds are ideal food for microorganisms. In
crops such as wheat, corn, tomatoes, and peanuts, up to 40 per cent of the
carbon absorbed through photosynthesis goes back to the soil through the roots.
It is not known for sure whether this process benefits the plant or is just a
waste of energy, but the carbon absorbed in this way helps microorganisms to
multiply.
Therefore, the role of microorganisms in plant metabolism
should be given more attention. Water-soluble and water-insoluble compounds are
excreted from the roots. Cells also fall off from the surface of the roots,
increasing the amount of organic matter in the root zone.
Microorganisms break down these compounds and produce carbon
dioxide and many other substances. The carbon cycle in the ecosystem depends
largely on these root exudates. Many biological, chemical and physical factors
affect this cycle. For example, when the roots are waterlogged or
over-irrigated, more carbon is released from the roots than usual.
This may be due to increased leakage of the root membranes in
such situations. There are many types of compounds around the roots. Their
nature and proportion depend on the type and age of the plant and the
environment. The type and proportion of microbes, insects and animals in the
root zone also depend on the nutrients released from the roots and their
amount.
Overall, the soil is
rich in fungi, but the root zone is rich in bacteria. Pseudomonas, abundant in the roots, and Enterobacteriaceae, abundant in the root
endophytic zone, are also important. Pseudomonas attaches to the roots with the
help of filaments called pili. For years, farmers have been unknowingly
receiving the help of bacteria called rhizobia.
The world of bacteria inside the root
This bacterium lives in the nodules of legume plants. It
converts nitrogen from the air into ammonia and gives it to the plants. Farmers
know that these root nodules are beneficial to the soil. Experienced farmers
also know that before planting legume plants in new fields, they collect some
soil from old legume fields and sprinkle it on new fields.
Microbiologists are trying to induce legume plants to form
more root nodules and to make the bacteria in them fix more nitrogen. Crop
plants help a lot in producing high yields in developing countries. And they do
not need to be applied with a lot of chemical fertilizers. In fact, if
artificial fertilizers are applied, the ability of bacteria to fix nitrogen
decreases.
Bacteria called Azospirillum also fix nitrogen. They live
separately outside the roots. They are very useful for plants with long roots
and many root nodules. Azospirillum appears to secrete chemicals that regulate
plant growth and encourage plants to take up more nitrogen from the soil or
from artificial fertilizers. It is best to have these regulating chemicals in
small amounts.
When the fungus
Trichoderma is introduced into the soil, plants grow and bloom faster, but no
one knows what the fungus does. Fungi in the root zone provide phosphorus to
the plants. Fungi called mycorrhiza, which live in symbiosis with the roots,
fix phosphorus. Their filaments spread through the soil, collect phosphorus and send it to the roots.
The spreading leaves also absorb water and provide it to the
roots. Which trait is most helpful in arid regions, but it is not clear whether
the fungus or the tree benefits from this cooperation. Bacteria can also fix
phosphorus, but they keep the phosphorus in the soil for themselves. Each type
of organism in the root zone performs some specialized function.
They appear to work together, for example, as bacteria that
feed on carbon from roots feed on protozoa. When the protozoa digest the
bacteria, they convert some of the nitrogen they contain into ammonia, which is
then deposited in the root zone.
Adding protozoa to the soil can increase the amount of
nitrogen available to plants by up to 75%. Microorganisms in the root zone can
be both beneficial and harmful. Some microorganisms help plants absorb
nutrients and water. Some microorganisms can cause diseases in plants.
Some can be used as
herbicides. The type and structure of the soil largely determine the nature of
the organisms in the root zone and their interactions. Plants do not grow well
in poor soil, but the microorganisms in it can indirectly help increase yields.
For example, polysaccharides released by microorganisms bind soil particles
to form agglomerate, which prevents soil erosion.
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