Question

A section of root nodule of chick-pea plant appears pink. 

(a) What is this color due to? 

(b) What type of condition does this pigment create? 

(c) Draw a schematic diagram to show progressive reduction of one molecule of nitrogen in the presence of nitrogenase enzyme to yield two molecules of ammonia.

Answer 1

(a) Pink colour is due to a pink colour pigment called leghaemoglobin.

(b) The pink colour pigment creates anaerobic condition.

Figure: Steps of conversion of atmospheric nitrogen to ammonia by nitrogenase enzyme complex found in nitrogen-fixing bacteria.