Question

In-plant mineral nutrition, elements are called macro or micro-elements depending upon their.
A. Relative presence in plant ash
B. Relative importance in plant growth
C. Relative amount required in plants
D. Relative availability in soil

Answer 1

Hint: Mineral nutrients play a very important role in the overall development and functioning of living organisms. Mineral nutrients are generally taken through the food as there is no inbuilt machinery for the production of mineral nutrients.

Complete answer:
All living organisms need mineral nutrients for the normal functioning of the body. These mineral nutrients are not produced in the body they are taken from an external source into the diet.
Importance of nutrients: These elements play an important role in the formation of organic compounds such as carbohydrates, fats, and protein. Elements are necessary for growth and development. The deficiency of these elements stops the plants from completing their vegetative and reproductive phase.
Mineral nutrients that are elements are grouped as macronutrients and micronutrients. These nutrients are grouped on the basis of its requirement in plants. Macronutrients are required in larger quantities whereas micronutrients are required in very small quantities. Elements required more than 10 millimoles per kg of dry matter of plant are macronutrients and elements required less than 10 millimoles per kg of dry matter of plants are micronutrients.
So, the correct answer is: In-plant mineral nutrition, elements are called macro or micro-elements depending upon their Relative amount required in plants.

Hence, the correct answer is option (C)

Note: Macronutrients in plants are: carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus, calcium, magnesium, and potassium.
Micronutrients: Iron, boron, chlorine, zinc, manganese, copper, molybdenum, nickel.
Nitrogen (N): It is required by the plants in the greatest amount. It is an important component of proteins, nucleic acids, amino acids, vitamins, hormones, chlorophyll, and cytochrome.
Deficiency symptoms: Chlorosis, stunted growth, anthocyanin formation.

Phosphorus(P): It is the constituent of the cell membrane, proteins, nucleic acids, ATP, NADP. Deficiency symptoms: Stunted growth, necrosis (death of the tissue), affect root growth, and fruit ripening.