What are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium? What is their role in N2 - fixation?
What are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium? What is their role in N2 - fixation?
Rhizobium is a symbiotic bacteria present in the root nodules of leguminous plants.
The basic requirements for Rhizobium to carry out nitrogen fixation are as follows:
(a) Presence of the enzyme nitrogenase.
(b) Presence of leghaemoglobin.
(c) Non-haem iron protein, ferredoxin as the electron-carriers.
(d) The constant supply of ATP.
(e) Mg2+ ions as co-factors.
Rhizobium contains the enzyme nitrogenase – a Mo-Fe protein – that helps in the conversion of atmospheric free nitrogen into ammonia.
The reaction is as follows:
N2+8e−+8H++16ATP→2NH3+H2+16ADP+16Pi
The Rhizobium bacteria live as aerobes under free-living conditions, but require anaerobic conditions during nitrogen fixation. This is because the enzyme nitrogenase is highly sensitive to molecular oxygen. The nodules contain leghaemoglobin, which protects nitrogenase from oxygen.
Rhizobium is a symbiotic bacteria present in the root nodules of leguminous plants.
The basic requirements for Rhizobium to carry out nitrogen fixation are as follows:
(a) Presence of the enzyme nitrogenase.
(b) Presence of leghaemoglobin.
(c) Non-haem iron protein, ferredoxin as the electron-carriers.
(d) The constant supply of ATP.
(e) Mg2+ ions as co-factors.
Rhizobium contains the enzyme nitrogenase – a Mo-Fe protein – that helps in the conversion of atmospheric free nitrogen into ammonia.
The reaction is as follows:
N2+8e−+8H++16ATP→2NH3+H2+16ADP+16Pi
The Rhizobium bacteria live as aerobes under free-living conditions, but require anaerobic conditions during nitrogen fixation. This is because the enzyme nitrogenase is highly sensitive to molecular oxygen. The nodules contain leghaemoglobin, which protects nitrogenase from oxygen.
