Question

Nitrogen fixation in root nodules of Alnus is brought about by

• A. Frankia
• B. Azorhizobium
• C. Bradyrhizobium
• D. Clostridium

Answer 1

The correct option is A Frankia

Frankia is a genus of the bacterial group termed actinomycetes - filamentous bacteria, that are noted for their production of air-borne spores. Frankia species are slow-growing in culture, and require specialised media, suggesting that they are specialised symbionts. They form nitrogen-fixing root nodules (sometimes called as actinorhizae) with several woody plants of different families, such as alder (Alnus species), sea buckthorn (Hippophae rhamnoides, which is common in sand-dune environments) andCasuarina (a Mediterranean tree genus).