Q. Which of the following forms of Nitrogen is taken up by Higher Plants?
Answer: Nitrates only
Notes: Plants do not get their nitrogen directly from the air. Plants absorb nitrogen from the soil in the form of nitrate (NO3−) and ammonium (NH4+). Nitrate is the form of nitrogen most used by plants for growth and development. Nitrate is the form that can most easily be lost to groundwater.
Nitrogen is a component of chlorophyll and therefore essential for photosynthesis. It is also the basic element of plant and animal proteins, including the genetic material DNA and RNA, and is important in periods of rapid growth. Plants use nitrogen by absorbing either nitrate or ammonium ions through the roots.