NEET BIOLOGY

Detailed explanation-1: -Azolla and the blue-green alga Anabaena azollae maintain a symbiotic relationship: the alga provides nitrogen to the fern, and the fern provides a habitat for the alga. This property of nitrogen fixation has made Azolla extremely important economically in the cultivation of rice, particularly in Asia.

Detailed explanation-2: -Symbiotic Nitrogen Fixation Particularly interesting is the symbiosis between the cyanobacterium Anabaena azollae and the leaves of the aquatic fern Azolla. This symbiosis is permanent and hereditary and is the only known mutualistic symbiosis between a pteridophyte and a diazotrophic prokaryote.

Detailed explanation-3: -The water fern Azolla harbors nitrogen-fixing cyanobacterium Anabaena azollae as symbiont in its dorsal leaves and is known as potent N2 fixer.

Detailed explanation-4: -Azolla is a water fern, a plant that is in a symbiotic association with the cyanobacterium anabaena which fixes atmospheric nitrogen.