Question

Root nodules which are present in plants are meant for fertilizers and are found in

• A. Certain leguminous plants
• B. Casuarina
• C. Both A and B
• D. None of the above

Answer 1

The correct option is C Both A and B

Nitrogen fixation that takes place by living things is called as biological nitrogen fixation. These include some bacteria and blue-green algae, which have acquired the capacity to fix atmospheric nitrogen during the evolutionary process by possessing a set of genes called as 'nif ' (nitrogen fixing) genes.

Blue-green algae like Nostoc establish symbiotic relationships in the corolloid roots of Cycas, or thalli of Anthoceros. Nitrogen fixation in legumes is the commonest type of symbiotic nitrogen fixation, which has been elaborately studied.

A soil bacterium called as Rhizobium infects roots of leguminous plants (belonging to family leguminosae) and forms the root nodules.

Casuarina is a genus of 17 species in the family Casuarinaceae, native to Australia, the Indian Subcontinent, southeast Asia, and islands of the western Pacific Ocean. It has root nodules.