Question

The figure given below is T.S. of {Azolla leaf, the filaments present in the cavity of the leaf are of _________

• A. Nostoc
• B. Tolypothrix
• C. Anabaena
• D. Oscillatoria

Hint:

{Azolla + Anabaena} is a classic example of symbiotic nitrogen fixation.

Answer 1

The Correct Option is C

Step 1: Understanding the structure of Azolla leaf.
Azolla is an aquatic fern that has a symbiotic association with a nitrogen-fixing cyanobacterium present in cavities of its leaf.

Step 2: Identifying the symbiotic organism.
The leaf cavities of Azolla contain filaments of Anabaena azollae, which fix atmospheric nitrogen and provide it to the plant.

Step 3: Conclusion.
Thus, the filaments present in the cavity of Azolla leaf are of Anabaena.