Question

Azolla a type of an aquatic fern, is used as a biofertiliser in a paddy field due to its ability to fix the atmospheric nitrogen. This is possible because of

• A. Association with algae
• B. Association with fungi
• C. Association with cyanobacterium
• D. Association with bacterium

Answer 1

Answer: (C)

Association with cyanobacterium

Many species of cyanobacteria are used as biofertilizers and help in nitrogen fixation. The species of cyanobacteria called as Anabaena azollae is commonly used in paddy fields for improving the quality and amount of yield. They are ideally suited for propagation in rice fields because they are capable of fixing atmospheric nitrogen in organic forms with the help of the enzyme nitrogenase present in the heterocyst cells. It helps to increase the nitrogen content of moist soil and water bodies, which can be used in increasing paddy yield.

Thus, the correct answer is option C.