Question

How do bacteria reach up to the cortex in nitrogen fixation?

Answer 1

Nitrogen fixation

1. The process of fixing atmospheric nitrogen into nitrates by bacteria is called biological nitrogen fixation.
2. Some bacteria reside in root nodules of certain leguminous plants and help in nitrogen fixation.
3. The rhizobium of these bacteria produce chemicals called nod factors which are perceived by the roots of leguminous plants.
4. These factors induce curling of the root hair which can then be easily penetrated by the rhizobium.
5. In this way, the bacteria form an infection thread.
6. Upon reaching the root, the bacteria trigger cortical cell division leading to the formation of root nodules.
7. Subsequently, the bacteria lose their cell wall and depend on the host plant for nutrition and shelter.
8. In return, it provides nitrogen in the form of soluble nitrates to the plant.