The concentration of essential element below which plant growth is retarded is termed as:

Step-by-step solution

A chemical nutrient that is necessary for plant growth and development is known as essential elements and they are 17 in number. Due to deficiency of it plants become unable to complete their life cycle. Critical concentration is the minimum concentration of mineral below that the plant growth will get retarded or stunted. If the concentration of the essential elements rises above the critical concentration then that leads to toxicity or the death of the plants.