Question

Which of the following is a flowering plant with nodules containing filamentous nitrogen-fixing microorganism?

• A. Casuarina equisetifolia
• B. Crotalaria juncea
• C. Cycas revoluta
• D. Cicer arietinum

Answer 1

The correct option is A Casuarina equisetifolia

Casuarina equisetifolia (whistling pine) is a common tropical seashore tree and is often planted as a windbreak. It forms a symbiotic relationship with filamentous soil bacterium Frankia. Frankia causes root hair deformation in a way that it enters the cortical cells and induces the nodule formations. Crotalaria juncea and Cicer arietinum are plants of the legume family. They form a symbiotic relationship with Rhizobia which bring about nodule formation in the root and multiply inside the nodule. They fix atmospheric nitrogen (N${}_2$) into organic form (NH${}_3$) by an enzyme called as nitrogenase. Cycas revoluta is a species of gymnosperm. It doesn't produce flowers.

Thus, the correct answer is option A.