Explain symbiotic biological nitrogen fixation.
There are some nitrogen fixing bacteria which live in close association with the plants in their roots as nodules. Both the bacteria and the plant are capable of independent existence but live with each other for a mutually beneficial association, hence called symbiosis. The bacteria covert atmospheric nitrogen into ammonia which can be absorbed by the plant to be utilized.
Nitrogen fixation: Process of conversion of nitrogen (N2) into ammonia (NH3).
There are two methods that change atmospheric nitrogen into usable forms through the process ofnitrogen fixation:
.During lightning and thunder, the high temperature and pressure in the air convert atmospheric nitrogen into oxides of nitrogen that can dissolve in water to produce nitric and nitrous acids. These fall along with rain.
.Certain forms of bacteria are able to convert atmospheric nitrogen into usable forms such as nitrates and nitrites. Such nitrogen fixing bacteria are commonly found in the roots oflegumes(plants of pulses) inside special structures calledroot nodules.
These usable forms of nitrogen are absorbed by plants to produce many compounds such as amino acids, which in turn form proteins.