Plant cells in culture are required to be provided with a continuous supply of 12 inorganic elements. Elements—Nitrogen, Phosphorous, Sulphur, Calcium, Potassium, and Magnesium—required in quantities greater than 0.5 mM/L are macro elements. Micro elements—Iron, Manganese, Copper, Zinc, Boron and Molybdenum—are needed in concentrations less than 0.5 mmol/L.

Nitrogen provided in the form of (NH₄)⁺ or (NO₃)^– can be provided in an organic or inorganic form each of which has a specific influence on in vitro morphogenesis. It is a constituent of amino acids, proteins, chlorophyll, and some growth hormones. Nitrogen is an important element contributing to overall pant growth both in vivo and in vitro. It is usually added up to 60 mM.

Phosphorous added as phosphate salt is needed in about 1.25 mM for cell division and for energy transfer and energy storage in plants.

Sulphur is provided as sulphate or from amino acids included in media such as cysteine, methionine, homocysteine, and glutathione. It is utilized for protein synthesis and required in concentration of around 1.5 mM.

Calcium in the form of calcium salts like calcium chloride in the concentration of about 3 mM is essential. It is involved in cell hormonal response to light, temperature, and so on. Calcium is needed for incorporation of phospholipids within the plant cell membrane and being an important component of cell walls, it is essential for cell membrane integrity.

Potassium in the form of potassium salts provided in the concentration of about 20 mM is required to be provided because it is needed for normal cell division and in the synthesis of chlorophyll, protein, and in the reduction of nitrates.

Magnesium in the form of magnesium sulphate in 1.5 mM concentration is to be provided. It is a co-factor of several enzymes and it is also a component of the chlorophyll molecule.

Microelements usually provided in trace amounts are needed as co-factors/catalysts or as inducers of enzyme synthesis.