Question

What are root nodules? How are they helpful?

Answer 1

Root Nodules:

1. Plants cannot use atmospheric nitrogen directly.
2. Some plants, such as leguminous plants form a symbiotic association with Rhizobium bacteria that fix atmospheric nitrogen to ammonia.
3. The Rhizobium bacteria, in return, get food from the plant.
4. Bacteria perform in the root nodules, specialized outgrowths from the root.
5. The roots of the leguminous plant release chemicals such as amino acids and flavonoids.
6. This attracts the Rhizobium bacteria towards the root hairs and attaches to the root surface.
7. The bacteria release nodulation factors that cause the curling of the root hair.
8. The bacteria gain entry into the cytoplasm by invagination of the cell membrane of the root hair, thereby forming an infection thread.
9. Simultaneously, nodule primordia are formed in the root cortex.
10. The nodule primordia house these bacteria, divide, and produce an outgrowth called root nodule.
11. The bacteria inside the root nodule produce nitrogenase enzyme, which enables nitrogen fixation.

Uses of Root Nodules:

1. The bacteria in the root nodules fix atmospheric nitrogen to ammonia with the help of the nitrogenase enzyme.
2. This can be used by the plant to produce amino acids for their growth and development.