Question

Azolla is used as a biofertilizer because:

• A. It has an association with nitrogen fixing Cyanobacteria
• B. It has an association with nitrogen fixing Rhizobium
• C. It multiplies very quickly to produce massive biomass
• D. It has an association with mycorrhiza

Answer 1

The correct option is A

It has an association with nitrogen fixing Cyanobacteria

$\bullet$ Azolla is an aquatic water fern which symbiotically associates with anabaena. Anabaena is a free living filamentous nitrogen fixing cyanobacterium. But it is also found in a symbiotic association with azolla to fix atmospheric nitrogen in usable form. Inturn, the bacterium gets a safe environment for survival. This little fern and its algal partner provide an important contribution as a biofertiliser in increasing the soil nitrogen content. Hence, azolla is majorily used in production of rice.
$\bullet$ Rhizobium is a symbiotic nitrogen fixing bacteria in association with the roots of leguminous plants.
$\bullet$ Mycorrhiza is a symbiotic association of fungal species with the roots of plants.