Conditions for N2 fixation : There are following conditions necessary for N2 fixation :
(1) A strong reducing agent like NADPH : It supplies hydrogen to N2.
(2) ATP as source of energy : It provides energy. For fixation of NH3 molecules, 8 ATP molecules are needed.
(3) The enzyme system : Nitrogenase is necessary for N2 fixation.
(4) Compound for trapping ammonia : Ammonia is very toxic and needs to be trapped in the form of amino acids.
(5) Leghaemoglobin : It is O2 scavenger and maintains anaerobic environment otherwise in the presence of O2 the enzyme nitrogenase is toxicated.
Why is that in certain plants deficiency symptoms appear first in younger parts of the plant while in others they do so in mature organs?
