Question

A nitrogen fixing cyanobacteria found in coralloid root of Cycas is

• A. Aulosira.
• B. Anabaena.
• C. Scytonema.
• D. All of the above.

Answer 1

The correct option is B Anabaena.

Cycas has unbranched, coral-like, apogeotropic coralloid roots, which harbour nitrogen-fixing colonies of cyanobacteria, like Anabaena. It fulfills the energy requirement of nitrogen fixers through fixed carbon in exchange for fixed nitrogen. The bacteria live as endosymbionts within the roots.

So, the correct answer is option B.