Question

Azolla is used as a biofertilizer, because it

• A. Multiplies very fast to produce massive biomass.
• B. Has association of nitrogen-fixing Rhizobium.
• C. Has association of nitrogen-fixing Cyanobacteria.
• D. Has asssociation of mycorrhiza.

Answer 1

The correct option is C Has association of nitrogen-fixing Cyanobacteria.

Azolla, a free floating freshwater fern has a symbiotic association with blue-green alga, Anabaena azollae. It lives in leaf cavities of fern. It has nitrogenase enzyme, therefore, can fix nitrogen. The decaying fern release same nitrogen to rice fields, where it grows abundantly and therefore, act as biofertilizer. Nitrogen is one of an essential elements needed by plants for their growth and Azolla’s high nitrogen content makes it an ideal biofertilizer. As a result, they can fix almost three times more atmospheric nitrogen than legumes.

Thus, the correct answer is option C.