Magnesium in the plant

Magnesium plays a vital role in plant nutrition and physiology

Those roles include ATP formation in the chloroplast, photosynthetic C02 fixation, protein synthesis, chlorophyll formation, phloem loading and enzyme activation just to name a few.

Chlorophyll molecules contain magnesium at its center, surrounded by 4 nitrogen atoms. Magnesium not only helps the chlorophyll absorb light, but it helps capture C02 that provides carbon for glucose formation within the leaf tissue.

Magnesium also is critical to moving the sucrose (how glucose is transported in the plant) out of the leaf tissue and out to the fruit, shoots, and roots. Without adequate magnesium in the plant, the leaf will continue to produce glucose, but it won't be able to exit the leaf to the plant. This is called phloem loading.

(this photo is courtesy of IPNI)

Research work done by Ismail Cakmak and Attila M. Yazici demonstrated that plants deficient in magnesium show a buildup of sucrose in the leaves which leads to a smaller root system. This effect on roots takes place before the development of visible leaf chlorosis. They also found that magnesium deficient older leaves contain 3.5 – 9 times more sucrose than leaves in with adequate magnesium and if magnesium is resupplied to deficient plants, the transport of sucrose out of the phloem will be restored within 12 hours.

Magnesium deficiency is most likely to show up on older leaves in the cool of the spring, and during the growing season when light intensity is highest. Cakmak and Yazici also demonstrated this in research where half a plant leaf was grown in regular light, and half of the leaf was under higher light intensity. They found severe magnesium deficiency under high light intensity and no symptoms under low intensity.

Tessenderlo Kerley’s MagThio® liquid fertilizer help is an effective method for providing in-season magnesium to the crop. Whether foliar fed or applied through the irrigation water, MagThio can be your insurance against phloem loading.

Download our product sheet on MagThio or download our SOP Book for more information.