What nutrient serves as a major building block for plant proteins?

Nitrogen is the nutrient that serves as a major building block for plant proteins due to its essential role in amino acid synthesis. Proteins are made up of amino acids, which contain nitrogen as a primary component. In plants, nitrogen is incorporated into amino acids, which are then used to create proteins necessary for various physiological functions, including enzyme activity, chlorophyll production, and overall growth and development.

Plants absorb nitrogen primarily in the form of nitrate or ammonium from the soil. Once in the plant, nitrogen contributes to critical processes such as photosynthesis and cellular metabolism, by forming the basis of amino acids that synthesize proteins. This highlights the importance of maintaining adequate nitrogen levels in the soil to support healthy plant development and optimize agricultural productivity.