Question

Critical elements for plant growth are:

• A. Na, K, and Ca
• B. Na, P, and Mg
• C. N, P, and K
• D. Mn, B, and Mo

Answer 1

The correct option is C

N, P, and K

The correct option is option C.

Explanation of the correct option:

• Nitrogen(N)

1. It is an important constituent of protoplasm.
2. It occurs in compounds such as amides, amino acids, alkaloids, purines, pyrimidines, etc.
3. Nitrogenous compounds play a major role in protein synthesis.
4. Genetic martial such as DNA as well as RNA contains nitrogenous bases like purines and pyrimidines.

• Phosphorous(P)

1. It is an important constituent of nucleic acids and phospholipids.
2. It is involved in metabolic processes like protein synthesis, photosynthesis, glycolysis, etc.
3. It enhances root growth.

• Potassium(K)

1. It is needed for protein synthesis, photosynthesis, and respiration.
2. It maintains cellular organization, cell membrane permeability, and plant growth.

Explanation of the incorrect options:

Option A:

1. Potassium(K) is needed to maintain cellular organization, cell permeability, and plant growth.
2. Calcium(Ca) plays an important role in lipid metabolism and controls the permeability of the cell membrane.
3. Sodium(Na) is a non-essential element that is not needed for plant growth and development.

Option B:

1. Sodium(Na) is a non-essential element and is not needed for plant growth.
2. Phosphorous(P) is an essential component of nucleic acids and phospholipids.
3. Magnesium functions as an activator of enzymes.

Option D:

1. Manganese is an activator of several enzymes involved in nitrogen metabolism.
2. Boron is involved in the translocation of carbohydrates and increases the absorption of water and calcium ions.
3. Molybdenum is a constituent of the enzyme reductase.
4. The above three are micronutrients and are needed in minute quantities in the plant.

Final answer: Critical elements for plant growth are N, P, and K.