Question

Discuss in short about symbiotic nitrogen fixers.

Anabaena, Nostoc, Rhizobium , Frankia, Xanthomonas, Aulosira

Answer 1

• Anabaena or Anabaena azollae are phototropic cyanobacteria (blue-green algae) which fixes the atmospheric nitrogen to provide nutrients to plants.

• Nostoc is a genus of cyanobacteria which also fixes atmospheric nitrogen.

• A Rhizobium is a group of bacteria present in the root nodules of leguminous plants which fix atmospheric nitrogen.

• Frankia is a genus of filamentous bacteria which helps in fixing nitrogen and shows symbiotic association with different plants.

• Xanthomonas is a genus bacteria which causes plant diseases.

• Aulosira is also a genus of filamentous cyanobacteria which are active nitrogen fixers in paddy fields.