Nodulated roots make the plant rich in

Which of the following is responsible for nitrogen fixation in an aquatic fern?

We find that $Rhizobium$ forms nodules on the roots of leguminous plants. Also,$Frankia$,another microbe,forms nitrogen-fixing nodules on the roots of the non-leguminous plant $Alnus$. What kind of relationship is observed between mycorrhiza and pine trees?

What will happen if $Rhizobium$ bacteria are introduced into a wheat field?

Knot-like bodies known as 'nodules' found in the roots of groundnut plant are produced by

Which one of the following can fix atmospheric nitrogen directly?