Classification of nutrients based on function

11 May 2020 - Articles

Nutritional elements can be classified according to their function  in the plant. In the coming months, Eurofins Agro will publish a series of articles covering the function of each of the different nutrients. We will also pay attention to deficiency symptoms, opportunities for testing and fertilization recommendations.

The four functional groups are:

Group 1: Essential elements that form organic compounds with carbon in the plant.
Group 2: Essential elements that form organic compounds that are important to the plant’s energy supply.
Group 3: Elements that are present in the plant as ions, and are therefore important in controlling the osmotic pressure in the plant sap (osmoregulation) and the transportation of assimilates in the plant.
Group 4; Elements that play an important role in activating enzymes in the plant (for example, chlorophyll formation).

Table 1: Classification of nutrients into functional groups for a plant.



Main function

1 Nitrogen (N) Quantitatively this is the most important element; a component of amino acids (the building block of proteins); part of chlorophyll. 
Sulphur (S) A component of proteins and cell membranes; renders heavy metals in the plant harmless; protects against pests.
2 Phosphorus (P) The main energy carrier in cells; a component of DNA; a component of cell membranes. 
Silicon (Si) A component of cell membranes (firmness, elasticity of the cell wall).
Boron (B) A component of cell membranes (firmness, growth of the cell wall).
3 Potassium (K) Controls the opening and closing of stomata. Protein synthesis and enzymes only work in the presence of K (and Ca).
Calcium (Ca) Controls the permeability of the cell membranes. Protein synthesis and enzymes work only in the presence of Ca (and K).
Magnesium (Mg) A component of the chlorophyll molecule; regulates the action of various enzymes.
Chlorine (Cl) Needed only in very low concentrations (comparable to trace elements) for osmoregulation.
Manganese (Mn) Important for the production of oxygen in photosynthesis; regulates the action of various enzymes.
Sodium (Na) Present in very low concentrations in the plant sap. For certain photosynthesis processes (the so called C4 and CAM plants) it is an essential trace element.
4 Iron (Fe) Important to certain enzymes and in photosynthesis (metabolism of organic acids). 
Zinc (Zn) A component of several enzymes; important for cell stretching in the stem and the main vein of the leaf.
Copper (Cu) Important to photosynthesis; ensures wood formation in plant parts.
Molybdenum (Mo) Important as a component of enzymes that control nitrogen fixation (e.g. in plants  with root nodules)


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