Question

What are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium? What is their role in N2 fixation?​

Answer 1

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 leg-haemoglobin, which protects nitrogenase from oxygen.

Answer 2

Reducing environment, Presence of nitrogenase enzyme and  leghaemoglobin are the conditions necessary for fixation of atmospheric nitrogen by Rhizobium.

Step by step explanation:

Let's explain each condition of necessary for fixation of atmospheric nitrogen by Rhizobium as follows:

• Reducing environment - It is useful to activate the nitrogenase enzyme.
• Presence of nitrogenase enzyme- It converts free atomspheric nitrogen to ammonia.
• Presence of leghaemoglobin - it is present in the Rhizobium bacteria which are located in the root nodules of plant , and these protect nitrogenase from oxygen.
• ATP source - Nitrogen fixation process require energy source.
• Ferridoxin - Feridoxin donates an electron to nitrogen and it becomes more active.
• Magnesium ions - These ions are act as co factors and improves the activity of nitrogenase enzyme.