Trace the events starting from the coming in contact of Rhizobium to a leguminous root till nodule formation. Add a note on the importance of leghemoglobin.
Ans:
(a) Rhizobium bacteria comes into contact with a susceptible root hair and begin to colonize the area of the roots.
(b) The root hairs curl up after being invaded by the bacteria.
(c) The infected thread formed in the roots carries the bacteria into the cortical tissue of the roots.The bacteria modify itself to Bacteroides that is rod-shaped, and as a result, the cortex and pericycle cells present in the roots divide.
(d) Division of the two cells in the cortex leads to the formation of nodules.
(e) A nodule is matured when it forms vascular tissues in continuation with the vascular tissues in the roots.Importance of
Leghaemoglobin: Nitrogenase is the most crucial enzyme that is required for N2 fixation. Nitrogenase is highly sensitive to oxygen, and this pink coloured pigment called leghaemoglobin acts as an oxygen scavenger and creates an anaerobic condition which is
necessary for normal functioning of nitrogenase.