Question

how are the enzymes nitrate reductase and nitrite reductase being made available to the nitrogen substrate in root and leaf tissues?

Answer 1

nitrogen is an essential element in the bilological system. they makes many key molecule including nucleoic acids which is codes for the genetic materials. Nitrogen is plently available in the atmosphere as N2 molecule but organisms cannot takeup nitrogen in such ways. most feasible way to take up nitrogen is through ammoinium slts which is NH4+. this is a molecule or ion formes by the reduction of n2 molecule. but plants are unable to do this on their own but some bacterias can do this effectively.

some of them are azetobacter rhizobium etc. they have specialized protein which can reduce nitrogen to ammonia namely nitrate reductase nitrogen oxidase nitrite reductase etc.

nitrogen has a triple bind which suggests it need high energy for the reduction. these bacterias with the help of a molybdinum based enzyme as mentioned above along with iron sulpher electron transport will reduce the atmospheric nitrogen to ammaonia which is the easily uptakeable form by the plants . most of the time the plants will be seen as a symbiotic association with such bacterias for nitrogen fixation. lants will produce food for the bacteia and the bactria inturn will give back ammonia for plant existence. these bacterias is often seen in leguminous plants inside root nodules which are specialised structure formed by roots.