Question

Why are root nodules useful for the plants?

Answer 1

Root nodules and their importance:

1. Root nodules are generally found in the roots of leguminous plants.
2. When nitrogen-fixing bacteria known as rhizobia enter the cells of a host plant, root nodules are formed.
3. When the soil has a low nitrogen content, the production of root nodules begins.
4. Cell signalling is used by the two symbiotic partners to establish their relationship and form nodules.
5. Legume roots release flavonoids that draw rhizobia to the root. Rhizobia gather close to the root hairs.
6. Nod factors, also known as nodulation factors, are secreted by rhizobia and induce the root hairs surrounding them to curl.
7. The nod factor binds to receptors found on the root hairs' plasma membrane, which causes the infection thread to develop.
8. The path for bacteria to penetrate epidermal cells is the infection thread.
9. Rhizobia then penetrate cortical cells, and a membrane generated from plants known as a symbiosome surrounds each bacterium.

Importance:

1. These nodules give place to some nitrogen-fixing bacteria such as Rhizobium, which fixes atmospheric nitrogen and convert it into ammonia. Plants can utilize this ammonia to derive nitrogen and fulfil nitrogen needs.
2. Thus, root nodules are helpful for plants as they help plants to fulfil their nitrogen needs and maintain soil fertility.