The concentration of the essential element below which plant growth is retarded is termed as critical concentration. The element is said to be deficient when present below the critical concentration.
Yes, we can find the values of critical concentration and deficient for minerals Fe and Zn by absorbing the morphological changes. If the concentrations of these elements are present below the critical values, then it may eventually lead to the death of the plant. Morphological changes are indicative ofrcertain element deficiencies and are called deficiency symptoms.