Question

Leghemoglobin function as
A. Oxygen Scavenger
B. Nitrogen Scavenger
C. $C{O_2}$
D. Hydrogen carrier

Answer 1

Leghemoglobin is the root nodule of the leguminous plants that contain the oxygen binding heme protein and found in the cytoplasm of the inflected nodules cells present at high concentrations. The transportation of the oxygen to the respiring symbiotic bacterial cells then analogously to hemoglobin transportation oxygen to the respiring animal’s tissue is the main function of the leghemoglobin.

Complete answer:
Rhizobia is the part of the symbiotic interactions between the bacterium and plant roots but not colonized by Rhizobium and also unable to synthesize the leghemoglobin. Like hemoglobin is red in color, leghemoglobin has structural and chemical similarities to hemoglobin. The bacterial symbiont within symbiotic roots originally found from the heme prosthetic group for plant leghemoglobin. The plant host strongly expresses heme biosynthesis genes within the nodule and activation of the genes that are correlated with the leghemoglobin gene.
Nitrogen fixation is an extremely cost effective process so for high concentration aerobic respiration required for the cells of the root nodules. Leghemoglobin maintains the high enough total oxygen concentration for aerobic respiration and also maintains the free oxygen concentration that is low enough to allow nitrogenous function. For example Casuarina is kind of an actinorhizal plant.

Therefore the correct option is (A).

Note:
It is ten times higher than the beta chain present in the human hemoglobin and acts as a scavenger. And hemoproteins are found in the nitrogen fixing root nodules of leguminous plants and also act as an oxygen carrier. In the cytoplasm inflected plant cells start proper functioning of the root nodules with the help of leghemoglobin.