The product(s) of reaction catalyzed by nitrogenase in root nodules of leguminous plants is/are:

MECHANISM OF BIOLOGICAL N₂ FIXATION:

It takes place in leguminous plants (Fabaceae) by the symbiotic bacterium Rhizobium, which forms nodules in their roots. N₂ is directly converted into an NH₄⁺ ion, which is used in plant metabolism. Root nodules act as the site for N₂ fixation. It contains all necessary biochemical components like enzyme nitrogenase, leghaemoglobin, that are required in N₂ fixation. Enzyme nitrogenase is a Mo–Fe protein & catalyzes the conversion of atmospheric N₂ to NH₃. 

The reaction takes place in two steps:

$$\begin{gathered} \left(i\right) N_2 + 8e^{-} + 8H^{+} +16ATP \stackrel{Nitrogenase}{\to } 2N{H}_3 + H_2 + 16ADP + 16Pi \\ \left(ii\right) 2N{H}_3 + H_2 \to 2N{H}_4^{+} + 2e^{-} \end{gathered}$$