Magnesium’s Role in Plant Growth


Magnesium is a component of several primary and secondary minerals in the soil, which are essentially insoluble, for agricultural considerations.  These materials are the original sources of the soluble or available forms of Mg.  But just what role does magnesium play in the development and growth of a plant?  How is it that magnesium (Mg) is an essential element for plant health and crop yield?  Because the fact of the matter is that it is highly essential if a plant is to grow healthily and successfully.

Magnesium plays various key roles in plant growth.  It plays one of the more central roles in photosynthesis as it is actually the key element of the chlorophyll molecule, which is the main component to the green pigmentation that healthy plants take on.  That is why if there is a deficiency of Mg, there can appear to be a yellowing of leaves because of the loss of functionality in the chlorophyll molecules.

Magnesium also helps in the process of taking phosphorus into the plant system.  It also aids in the carrying of phosphorus throughout the plant system to promote sufficient levels of P all throughout the entire plant.  Mg also functions as an enzyme activator as well as a vital component of several enzymes.  It also is highly necessary for the making and production of proteins, fatty acids and oils.

Several different sugars and starches in plants are also dependent upon Mg to be transformed into a form which the plant can utilize in the system.  If there is not enough magnesium available in the plants, this could mean that there is not going to be enough available to transform sufficient sugars and starches to keep growing and reach its full potential.

There are a wide variety of things and factors that can affect how easily Mg is made available for the plant to take up and use.  If there is naturally less magnesium in the soil then obviously it will be more difficult for the plant to take up enough magnesium without fertilization and additional nutrient supplements.  Or if the pH in the soil is lower, the uptake of Mg can be slowed.

Stunted growth or leaves which are more of a uniformly pale yellow or brown could mean that there is a magnesium deficiency.  However, these symptoms could be symptomatic of several different nutrient deficiencies.  For example, a yellowing of the leaves could mean a nitrogen deficiency as well as a magnesium deficiency.  Or a retardation in plant or crop growth could mean any number of different nutrient deficiencies.  It takes a balance in all elements if a plant is to reach its full potential.  So how can one tell and diagnose a specific magnesium deficiency if these signs could be a symptom of several different nutrient deficiencies?

In a magnesium deficiency, one should make sure to check plants regularly because one of the more specific symptoms for a magnesium deficiency is where the symptoms first start appearing.  In an magnesium deficiency, the yellowing of the leaves starts in the lower leaves.  The interveinal chlorosis then begins to take place, yet the veins remain green.  There will also be a decrease in the size of the area for photosynthesis. The natural side effect of a decrease in the area of photosynthetic reactions is a lower plant height as well as the accumulation of dry matter is slowed down severely.