Question

Nitrogen is abundant in the atmosphere but plants cannot use gaseous form of nitrogen. Why.

Answer 1

Plants can’t absob nitrogen direcly from atmosphere (although is is abundant around here) because of the nature of molecular nitogen. in molecular nitrogen, two atoms of nitrogen are bonded with each other by three covalent bonds (one is sigma, the other two are pi bonds); and this bonding is too strong to be broken by any of the biochemical processes happening in the plant cells as it requires a good amount of energy which if plant cells provide would cost them their survival. So, there is a cheaper way for them to obtain nitrogen, that you might be knowing.