Question

Give the biochemical events occurring in the root nodule of a pulse plant. What is the end product? What is its fate?

Answer 1

Nodule Formation:

1. Rhizobium bacteria contact a susceptible root hair and begin to divide near it.
2. After successful infection, the root hair curls.
3. The infected thread of the root carries the bacteria to the inner cortex. The bacteria get modified into rod-shaped bacteroids. This causes the inner cortical and pericycle cells to divide.
4. Division and growth of cortical and pericycle cells result in nodule formation.
5. A mature nodule is complete with vascular tissues, which are continuous with the vascular tissues of the root.

Importance of Leghaemoglobin: Leghaemoglobin works as an oxygen scavenger and thus creates anaerobic conditions in the root nodule of a legume. Nitrogenase is highly sensitive to oxygen and needs an anaerobic condition to maintain its existence.