Which one of the following mineral nutrients is not a macronutrient required by plants?

Correct option is A

Manganese (Mn) is a micronutrient, not a macronutrient, required by plants. While it plays an essential role in enzyme activation, photosynthesis, and nitrogen metabolism, it is needed in much smaller quantities compared to macronutrients. Macronutrients (N, P, K, Ca, Mg, S) are required in larger amounts for plant growth, while micronutrients (Mn, Zn, Fe, Cu, B, Mo, Cl, Ni) are needed in trace amounts.

Information Booster:

1. Macronutrients: Essential elements required in large quantities (Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, Sulphur).
2. Micronutrients: Required in small quantities but still vital (Manganese, Iron, Zinc, Copper, Boron, Molybdenum, Chlorine, Nickel).
3. Manganese helps in photosynthesis and enzyme activation, but in excess, it can be toxic to plants.
4. Magnesium is a component of chlorophyll, making it essential for photosynthesis.
5. Phosphorus is vital for energy transfer (ATP), root development, and flowering.
6. Sulphur is needed for amino acid synthesis (cysteine and methionine) and enzyme function.