Effect of Mg Deficiency on Antioxidant Enzymes Activities and Lipid Peroxidation

The importance of the physiological role of nutrient elements in plant behavior concerning higher and morestable yield, using the durum wheat variety P1252 as model plant, was examined under hydroponic conditions.To investigate the effects of Mg deficiency, the element was eliminated from the media solutions. Resultsshowed that Mg elimination decreased the chlorophyll content. Lack of Mg only affected guaiacol peroxidase(GPX) and catalase (CAT) activities significantly. The SOD/APX+GPX+CAT ratio as an index of assessing thebalance between H2O2-producing and H2O2-scavenging enzymes increased leading to the accumulation of H2O2in cell. The elevation of SOD/APX+GPX+CAT ratio and H2O2 accumulation indicates the occurrence ofoxidative stress in leave cells under Mg deficiency. Lack of magnesium (Mg) resulted in considerable increasein other oxidative stress indices, cell death and Malondialdehyde (MDA). The reason is the occurrence ofHaber-Weiz reaction in absence of Mg and production of hydroxyl radical, a very dangerous radical, leading toincreasing damage of cell biomolecules and their apoptosis.