Read this article to learn about the role of nitrogen in the life of the plants and different sources of nitrogen to plants.
Role of Nitrogen in Plants:
Nitrogen is a universally occurring element in all the living beings. Apart from water and mineral salts the next major substance in plant cell is protein (about 10-12% of the cell). These proteins which are building blocks of the protoplasm are made up of nitrogenous substances called as the amino acids which in turn are synthesized when inorganic nitrogen of the environment is converted into organic nitrogen inside the plants. (Plant cells are therefore, unique in their ability to convert inorganic nitrogen into organic nitrogen).
Nitrogen is also constituent element of many other important organic compounds like chlorophylls, cytochromes, alkaloids, many vitamins (which serve as functional groups of many enzymes) and above all of nucleic acids and thus plays a very important and fundamental role in metabolism, growth, reproduction, and heredity.
Sources of Nitrogen to Plants:
(1) Atmospheric Nitrogen (Molecular Nitrogen):
Although about 78% of the earth’s atmosphere is composed of nitrogen, the majority of the plants cannot utilise from of nitrogen. Only some bacteria, some blue-green algae, leguminous plants (having root nodules) etc. can fix atmospheric nitrogen.
(2) Nitrates, Nitrites, Ammonia in the Soil (Inorganic Nitrogen):
Among these, the nitrate is the chief form of nitrogen taken up by the plants from the soil.
(3) Amino Acids (Organic Nitrogen) in the Soil:
Many soil micro-organisms make use of this form of nitrogen. Sometimes it may also be taken by higher plants.
(4) Organic Nitrogenous Compounds in Bodies of the Insects:
Insectivorous plants fulfill their nitrogen requirement by catching the small insects and digesting them.