Mineral Nutrition Test - 8

Ammonia is first oxidised to nitrite by the bacteria Nitrosomonas and/or Nitrococcus. The nitrite is further oxidised to nitrate with the help of the bacterium Nitrobacter Pseudomonas.

Decomposition of organic nitrogen of dead plants and animals into ammonia is called ammonification.Some of this ammonia volatilises and re-enters the atmosphere but most of it is converted into nitrate by soil Bacteria.

N²⁻ fixing bacteria, especially roots of legumes, can fix this atmospheric nitrogen into biologically usable forms. Nitrogen fixation requires a strong reducing agent and energy in the form of ATP. Nitrogen-fixation is accomplished with the help of nitrogen fixing microbes mainly rhizobium.

Nitrogen exists as two nitrogen atoms joined by a very strong triple covalent bond (N ≡ N) N₂.

Biological nitrogen fixation (BNF) is the term used for a process in which nitrogen gas (N₂) from the atmosphere is incorporated into the tissue of certain plants. Only a select group of plants is able to obtain N this way, with the help of soil microorganisms.

The conversion of atmospheric nitrogen to ammonia by nitrogenase enzyme complex found in nitrogen-fixing bacteria(biological nitrogen fixation).

Except pseudomonas all other bacteria are free living, nitrogen fixing microbes.

The xylem is the part of plant which conducts water from one location to another. But all the others are sources of nitrogen.

Infected thread carries the bacteria to the inner cortex. The bacteria get modified into rod-shaped bacteroids and cause inner cortical and pericycle cells to divide. Division and growth of cortical and pericycle cells lead to nodule formation.

Sergei Winogradsky discovered the biological nitrogen fixation during which atmospheric nitrogen is converted into nitrates and nitrite.