The Effect of Heavy Metals on Soluble Sugars Content, Total Protein and Activity of Antioxidant Enzymes in Wheat

Todays, pollution caused by heavy metals is a major concern in agriculture field. Heavy metals, by accumulation in soil and uptake by plants, inter into food chain and causes toxicity in the plants and consumers of these plants. Cadmium and mercury are  two dangerous and carcinogenic substances that  their amounts is increasing in natural ecosystems through human activities resulting in decreased proteins production, inactivation of some enzymes, interfering with variety of reactions and cell functions and cessation of cell growth and development and in general is a great treat to agriculture. For this purpose, a factorial experiment in a completely randomized design with three replications was conducted in greenhouse of Mohaghegh university of Ardabil in 1391. The experiment consisted of mercuric chloride treatments (with concentrations of 10 and 20µM), cadmium chloride treatment (0.5 mM), interaction between cadmium and mercury in two levels (10 µM of mercury with 0.5 mM of cadmium, 20 µM of mercury with 0.5 mM of cadmium) and control seedlings. The results showed that in Gonbad cultivar treated by cadmium, mercuric and the interaction of both heavy metals, the soluble sugar content and total protein were increased, but the activity of antioxidant enzymes decreased. In Tajan cultivar, total protein content was reduced but the activity of peroxidase, catalase and polyphenol oxidase enzymes (but for interaction of both heavy) was increased. Due to the activities of antioxidant enzymes to reduce the damage caused by various stresses, so seems that the increased activity of these enzymes in Tajan can increase stress resistance compared help. The Gonbad of other mechanisms also probably used for tolerance.