Question

Unicellular symbiotic organisms that improve the yield of legumes by

• A. Fixing nitrogen without colonizing roots of host
• B. Fixing atmospheric nitrogen and colonizing roots of host
• C. Inducing the host plant to absorb more phosphorous
• D. Stimulating the host plant to become tolerant to drought

Answer 1

The correct option is B Fixing atmospheric nitrogen and colonizing roots of host

Leguminous crops harbor root nodule bacteria in their roots. The roots are infected by Rhizobium bacteria, which after infection gets converted into bacteroids and fixes nitrogen. For the purpose of fixing nitrogen, bacterial gets energy from the host plant and in return makes available fixed nitrogen to the host plant.