Nitrogen

NITROGEN It is the most important nutrient for plant development, as it is the main element of vital biomolecules such as proteins and chlorophyll. Therefore, N is a necessary element in all phenological stages of the plant, especially in the development of leaves and shoots where chlorophyll is most abundant.
In the plant, N is distributed in 3 groups:
More than 50% is in high-molecular-weight compounds (proteins and nucleic acids); the remainder is in the form of soluble organic nitrogen (amino acids, amides, amines, etc.) and inorganic nitrogen (mainly nitrate and ammonium ions). Its content in the total dry weight of the plant ranges between 1,5% and 5%.

ABSORPTION

In the soil, nitrogen is found primarily in the organic N fraction. However, plants absorb it through their roots and leaves in mineral form as ammonium nitrogen (NH4+) and nitrate nitrogen (NO3-). Therefore, the processes of N mineralization in the soil, controlled by microorganisms, are essential.

There are genera of bacteria, such as Rhizobium and Frankia, that, in symbiosis with leguminous plants and other plant families, are capable of fixing atmospheric nitrogen. Ammonia, in gaseous form, can also enter the plant through the stomata. In both processes, the final product is ammonium.