What is the role played by root nodules found on the roots of leguminous plants?

Why are root nodules useful for the leguminous plants?

Root nodules are founds in

Root nodules in leguminous plants:

Name the bacteria found in root nodules of leguminous plants.

We find that Rhizobium forms nodules on the roots of leguminous plants. Also Frankia another microbe forms nitrogen fixing nodules on the roots of non-leguminous plant Alnus. (a) Can we artificially induce the property of nitrogen-fixation in a plant, leguminous or non-leguminous ? (b) What kind of relationship is observed between mycorrhiza and pine trees ? (c) Is it necessary for a microbe to be in close association with a plant to provide mineral nutrition ? Explain with the help of one example.

The microbe that produces root nodules on the root of Alnus is

Name the red pigment present in the root nodules of leguminous plants