Azola

Azolla is a small leaf floating pteridophyte of Azollaceae family; it forms a symbiotic relationship with the Cyno-bacterium Anabaena which fix atmospheric nitrogen and gives the plant access to the essential nutrients. Cyano bacteria obtain energy through photosynthesis and very often Cyano bacteria phylum is alternatively called “blue-green algae”. Azolla keeps symbiotic blue-green algae, Anabeana Azollae, which simultaneously fixes and assimilates the atmospheric nitrogen. Azolla, in turn, provided the necessary carbon source and favourable environment for the growth and development of the algae.