Micronutrients:
Such essential elements which are found less than 1.0 mg per gram of dry weight of plant are called micronutrients. Although these are found in low amount, they play an important role in plant metabolism. These are also called trace elements. These are eight in number. Example: B, Cu, Cl, Mn, Mo, Zn, Fe and Ni.
Micronutrients:
Elements which are found in plants in an amount less than 1.0 mg per gm of dry weight are called minor or micronutrients. Although required in very small amount, they play a significant role in plant metabolism. These are also called trace elements. These are nine in number – B, Cu, Cl, Mn, Mo, Ni, Zn, and Fe.
Besides the above 17 elements, some other elements have also been found beneficial in higher plants. These are called beneficial or functional elements. Eg: Na, Si, Co and So.
- Essential elements are also classified on the basis of their function or role in plant nutrition. These categories are:
- Structural elements: The essential elements which are constituents of biochemicals are called structural elements. Example: e, h, o, n.
- Energy-related elements: Such essential elements are useful in energy-related biochemical reactions in the plant. Example: Phosphorous in ATP and Mg in chlorophyll.
- Enzyme activators: These essential elements act as activator or inhibitors of different enzymes. Example: Mn, Zn, Mo. Mg, Etc.