Botany - Mineral Nutrition Question with Solution | TestHub
If by radiation all the nitrogenase enzymes are inactivated, then which of the following will not occur?
(i) Fixation of atmospheric NO2
(ii) Conversion from nitrate to nitrite in legumes
(iii) Fixation of nitrogen in legumes
(iv) Conversion from ammonium to nitrate in soil
Options:
Answer:
Solution:
The process by which N2is reduced to NH4+is called nitrogen fixation. Nitrogenase enzyme catalyzes this reduction. It is only carried out by prokaryotic microorganisms. Principle N2-fixers include certain free-living cyanobacteria in symbiotic associations with fungi lichens or with ferns, mosses, and liverworts, and by bacteria or other microbes associated symbiotically with roots, especially those of legumes. About 15 percent of the nearly 20,000 species in the Fabaceae (leguminosae) family have been examined for N2fixation, and approximately 90 percent of these have root nodules in which fixation occurs. So without active nitrogenase enzyme, there will be no N2fixation in legumes.
