Question

What is the role of the bacteria in root nodules of legumes?

• A. To convert oxides of nitrogen into soil nitrates.
• B. To convert atmospheric nitrogen gas into soil nitrates.
• C. To convert soil nitrates into gaseous nitrogen.
• D. To convert plant proteins into ammonia.

Answer 1

The correct option is B To convert atmospheric nitrogen gas into soil nitrates.

Rhizobium fixes nitrogen in symbiotic association with roots of leguminous plants. Initially, the bacteria grows in soil near the roots of higher plants where they fail to fix the nitrogen. In the root nodules, the enzyme nitrogenase in the bacteria helps in the conversion of the atmospheric nitrogen to the nitrates which can be used by the plants.

Thus, the correct answer is option B.