Question

Which of the group of elements is not essential for a normal plant?

• A. K, Ca, Mg
• B. Fe, Zn, Mn, B
• C. Pb, I, Na
• D. Mg, Fe, Mo

Answer 1

The correct option is C Pb, I, Na

The plant ash reveals the presence of 40 elements but all are not essential for plant nutrition, only a few are essential for growth and development of plants. These are called as the essential elements. The essential elements may be grouped as major elements or macronutrients and trace elements or micronutrients, based on their requirement by plants.

Major elements or macronutrients are required in large amounts and form the plant constituents. These include carbon, hydrogen, oxygen, nitrogen, phosphorus, potassium, calcium, magnesium and sulphur. These elements form an integral part of complex organic molecules. Some of these elements help in the functioning of enzyme systems. The sources of macronutrients are generally the soil or the atmosphere.

Trace elements or micronutrients are elements, like iron, boron, manganese, copper, zinc and molybdenum. They are required for plants only in very small amounts but these are indispensable for the normal growth and development of plants.

Lead, Iodine and sodium are generally not required by plants and are non essential elements for plant mineral nutrition.