Question

What are essential elements for plants? Give the criteria of essentiality? How are minerals classifieds depending upon the amount in which they are needed by the plants?

Answer 1

An element that fulfils the essentiality criteria is called an essential element for plants. Following are the various criteria for essentiality.

1. The element must be essential for supporting average growth and reproduction in plants.
2. The element requirement must be specific and not replaceable by any other element.
3. The element must be directly involved in metabolism in the plant.

On the basis of the amount in which plants need minerals, they are divided into two categories, viz. macronutrients, and micronutrients.

Macronutrients: Elements present in large amounts, i.e. more than 10 moles per kg of dry matter, are called macronutrients – examples: carbon, hydrogen, oxygen, nitrogen, etc.

Micronutrients: Elements present in small amounts, i.e. less than 10 moles per kg of dry matter, are called micronutrients – examples: iron, calcium, magnesium, etc.