Interesting Facts about Nitrogen and Plant Growth
Nitrogen is a gas that is essential for plant growth. It is present in the surrounding atmosphere and is the most common gaseous element that accounts for 78 % of the earth’s atmosphere.
Even though Nitrogen is present in the atmosphere in abundance, plants cannot use Nitrogen in its gaseous form. Plants can absorb Nitrogen from the soil only in the form of ammonium, nitrites, and nitrates.
A little about Nitrogen
Nitrogen is a gas with a chemical symbol N. It is nonmetallic, colorless, odorless, tasteless and has an atomic number of 7 with an atomic weight of 14.0067. Nitrogen is slightly lighter than air and has a density of 1.251 grams/liter at 0 degrees Centigrade and a specific gravity of 0.96737.
Why Nitrogen is important for plant growth?
Nitrogen is an important component in plant cells that help to perform metabolic functions essential for growth and reproduction of plants. Presenting the ways in which Nitrogen helps plants to grow, flourish and reproduce -
Chlorophyll is a green color pigment that helps in the process of photosynthesis. Photosynthesis is a process through which plants get the energy that they need to grow and reproduce.
During photosynthesis, chlorophyll in the leaves absorbs light energy from the sun and uses this energy to split water molecules into hydrogen and oxygen. The oxygen is released into the atmosphere, and the hydrogen and carbon dioxide are used to form glucose that gives energy for the plants. Some of this glucose is stored in the plant to be used as and when needed.
Nitrogen is part of the chlorophyll molecule that gives the green color to the plants. In the absence of Nitrogen, the chlorophyll content is depleted, and the process of photosynthesis is considerably reduced. This results in stunted growth, yellowing of leaves and wilting of plants.
Amino Acids & Proteins
Nitrogen is a major component of amino acids that form the building blocks of protein.
Amino acids are organic compounds that are made of carbon, hydrogen, oxygen, nitrogen. These amino acids combine in different ways to form proteins.
There are twenty amino acids that plants combine to from proteins and all these twenty proteins have to be produced by the plants. Without Nitrogen the plant cannot produce amino acids.
Lack of Nitrogen will lead to reduced production of amino acids by the plant cells and this in turn will lead to lack of protein needed for the metabolic functions of plant cells.
Some proteins in plants act as structural units in cell walls and cell membranes and other proteins act as enzymes that enable biochemical reactions essential for plant growth and reproduction.
The genetic material DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid) present in plants cells are made of Carbon, Hydrogen, Oxygen, Nitrogen, and Phosphorous. Without Nitrogen the genetic material cannot exist.
The DNA contains the traits of a specific plant and when the plant cells reproduce this information is copied and passed onto the new cells. The RNA consist of the instructions passed on by the DNA for the manufacture of proteins.
DNA and RNA
DNA is made of two linear strands twisted in the shape of a double helix. These strands are made of a phosphate-deoxyribose sugar backbone connected across by rungs of the nitrogenous bases such as adenine (A), Guanine (G) Cytosine (C) and Thymine (T). In the double-stranded helix Adenine pairs with Thymine and Guanine with Cytosine.
The RNA is made of Ribonucleic acid and it has the coding information passed on by the DNA for the manufacture of proteins. It is single stranded and is made of phosphate-ribose sugars and the nitrogenous bases Adenine, Thymine, Guanine, and Uracil.
Nitrogen is vital for the formation of the nitrogenous bases. Without the nitrogenous bases the DNA and RNA molecules would be incomplete and they will not perform the functions vital to the existence of plants.
How do plants obtain Nitrogen from the air?
Nitrogen is the most abundant element in the air, but it is not present in a form that the plants can use. The molecular Nitrogen present in the air has two Nitrogen atoms that are triple bonded to each other. This bond is strong and difficult for the plants to break in order to obtain a form of Nitrogen that they can use.
The process of breaking down of two Nitrogen molecules is called Nitrogen Fixation.
In a symbiotic relationship the Rhizobium bacteria present in the roots of Leguminous plants fix the Nitrogen in the atmosphere and converts it into ammonia, a form that plants can absorb and use for growth and reproduction. The leguminous plants in turn supply carbon to the Rhizobium bacteria.
A small amount of Nitrogen in the atmosphere is fixed during lightning and solar radiation.
Plants also obtain the Nitrogen that they need through Nitrogen fertilizers that are added to enrich the soil.
Lack of Nitrogen in the soil can lead to a low yield of weak crops. Nitrogen fertilizers are added to the soil to enable the growth of healthy plants and a better yield of crops.
Farmers test the soil to determine the Nitrogen content of the soil and depending upon the crops to be grown and the yield to be achieved the amount of Nitrogen fertilizer to be added to the soil is calculated.
If plants are supplied with excess of Nitrogen they begin to produce protoplasm at a rapid rate but at the same time, they are not able to produce the cellular structures needed to enclose the protoplasm in cells. This results in weak plants that can be damaged easily thereby leading to a low yield of crops.
Nitrogen fertilizers are used to makeup for the lack of Nitrogen in the soil. Nitrogen fertilizers must be used in such a way that they do not leach out from the soil and pollute the environment.
Nitrogen is a gas that enables plants to perform metabolic functions essential for their growth and reproduction. Nitrogen is the most abundant element in the air, but it is not present in a form that the plants can use.
Plants obtain Nitrogen that they need through a process called Nitrogen Fixation. A small amount of Nitrogen is fixed during lightning. Leguminous plants get the Nitrogen that they need through a symbiotic relationship with the Rhizobium bacteria. Plants also obtain Nitrogen through the fertilizers that are added to the soil.
Nitrogen is a part of chlorophyll, amino acids, proteins, and genetic material in plants that are essential for the process of growth and survival of plants.
Without access to the optimum level of Nitrogen plants will not be able to grow, flourish and reproduce.
© 2017 Nithya Venkat