Question

Plants cannot absorb nitrogen in the form of

• A. $N_2$
• B. ${{\mathrm{NO}}_2}^{-}$
• C. ${{\mathrm{NO}}_3}^{-}$
• D. ${{\mathrm{NH}}_4}^{+}$

Answer 1

The correct option is A $N_2$

Nitrogen is a very essential element for the normal growth of plants. It is one of the major constituents of proteins, nucleic acids, vitamins and hormones.
Plants cannot directly absorb atmospheric nitrogen ($N_2$) and hence it is converted into a form that plants can absorb. This is called nitrogen fixation and bacteria play a major role in nitrogen fixation. Plants can absorb nitrogen in the form of nitrite (${{\mathrm{NO}}_2}^{-}$), nitrate (${{\mathrm{NO}}_3}^{-}$) and ammonium (${{\mathrm{NH}}_4}^{+}$) ions.