Assertion : Nitrogen-fixing bacteria in legume root nodules survive in oxygen-depleted cells of nodules. Reason : Legheamoglobin completely removes oxygen from the nodule cells.

Step-by-step solution

Symbiotic nitrogen fixation occurs in legume plants. It takes place in the Rhizobium bacteroids which are located within root nodules cells. The important enzyme Nitrogenase (synthesised by Rhizobium ) that reduces N ₂ , is oxygen sensitive. It can only function at low oxygen concentration. This low oxygen concentration in bacteriod is provided by leghaemoglobin. Leghaemoglobin (pink in colour) is a form of pigment found in the nitrogen fixing root nodules of legume. It binds oxygen and thus protects the nitrogen f