Magnesium plays a role as a cofactor of almost 300 enzymes involved in a wide range of biological activities including energy metabolism, DNA repair, protein synthesis and muscle function.
Magnesium is the central atom in chlorophyll and consequently, magnesium is vital for photosynthesis and plant growth. Magnesium is also used by plants to activate certain enzymes, build proteins and chlorophylls, activate hydrolytic enzymes, transport ions in embryo growth and cell division, and many more processes. Magnesium is an essential nutrient for plant growth, development and stress responses. Magnesium is required in many biochemical processes that occur within plants, including photosynthesis and chlorophyll production. If a plant does not have enough magnesium to make the enzymes that it needs, it will be unable to produce chlorophyll or grow well (1). Magnesium is used by plants for building proteins and activating enzymes.
Magnesium is a major deficiency in most gardens and can occur even in ground rich in other nutrients. The signs of magnesium deficiency are very slow to appear, with the plant suffering from lack of chlorophyll and overall vigour. It can even become locked out by high levels of calcium or potassium. A good way to ensure that this does not happen is to use a magnesium-containing foliar spray, such as a weak solution of calmag supplement. Excessive amounts of magnesium can cause calcium and potassium to become available in the plant tissue. Dark-green foliage may indicate too much magnesium, as well as slow growth rates. Calcium deficiencies are also associated with dark green leaves—and slower growth if not corrected.
Approximately half of all magnesium is found in seawater and about one-third is found in soil. It is also present in many rock types and sedimentary deposits. Magnesium salts are very common in nature and include carbonates, sulphates, chlorides, nitrates, and bicarbonates of magnesium. Magnesium can be identified by its characteristic "atom" symbol: Mg