Question

Why are root nodules useful for the plants?

Answer 1

The roots of leguminous plants bear nodules. Nitrogen fixing bacteria, Rhizobium resides inside these modules. Rhizobium can directly utilises atmospheric nitrogen and converts it into nitrogenous compounds like ammonia and nitrates. In this way plants get easy access to these chemicals which are good for plant growth. This is the reason that root nodules are useful for plants.