Question

Which one of the following is not an essential micronutrient?
A. Sodium
B. Zinc
C. Boron
D. Copper

Answer 1

The nutrients required by plants are of two types depending on the requirement. They are classified as micro and macronutrients. Under micronutrients, they are further classified into essential and non-essential micronutrients.

Complete answer:
The nutrients that are required by plants in small quantities are known as micronutrients. The element sodium is not essential for the majority of the plants. Since it is required in very small quantities as well as it is not essential for many plants. It is known as a non-essential micronutrient.
Considering the other given options:
Zinc is an essential micronutrient required by plants. It is involved in the formation of chlorophyll as well as in the formation of some carbohydrate molecules. It is also involved in the synthesis of Auxin which helps in the shoot elongation. Thus it is not an appropriate option.
Boron is also an essential micronutrient involved in plant growth. It helps in the cell wall formation as well as mediates cell division. Thus it is not the appropriate option.
Copper is also an essential micronutrient. It is involved in photosynthesis as well as in lignin formation. Thus it is not the appropriate option.
Thus from the above-given options, the most appropriate answer is A, i.e., Sodium is not an essential micronutrient.

Note: Macronutrients are those elements that are required by plants in larger amounts. The different macromolecules are nitrogen, phosphorus, and potassium, calcium, sulfur, and magnesium. Out of these nitrogen, phosphorus and potassium are the most important nutrients for plant growth and development.