Ques. 1AIPMT 2000
Which aquatic fern is used to increase the yield in paddy crop?
- Salvinia
- Isoetes
- Marsilea
- Azolla
Answer
(4) Azolla
Solution
Azolla is a small floating water fern that harbours the nitrogen-fixing cyanobacterium Anabaena in its leaves.
⇒ As per NCERT, cyanobacteria such as Anabaena and Nostoc fix atmospheric nitrogen and act as biofertilisers in paddy fields.
∴ Azolla grown in paddy fields enriches the soil with nitrogen and increases the yield.
Answer: (4)