EFFECTS OF CHLORIDE SALINITY ON NON-ENZYMATIC ANTIOXIDANT ACTIVITY, PROLINE AND MALONDIALDEHYDE CONTENT IN THREE FLUE-CURED CULTIVARS OF TOBACCO

摘要

High salinity causes ion poisoning and subsequent oxidative stress. During oxidative ion poisoning, non-enzymatic defense systems such as carotenoids, phenols and flavonoids are activated. In this study, the effects of various concentrations of chloride in the irrigation water (10, 20, 40 and 80 mg/l) on carotenoids, phenols, flavonoids and proline content in three varieties of tobacco plant (Virginia, Kentucky and Cooker) were investigated. Malondialdehyde content was also measured, as a lipid peroxidation index. The highest level of ?-carotene was observed in Virginia at 10 mg/l chloride and the lowest quantity was seen in Kentucky at 20 mg/l chloride. Kentucky had the highest and lowest levels of flavonoids at 80 and 40 mg/l concentrations of chloride respectively. Highest phenol content was observed in the presence of 10 mg/l chloride in Virginia. Maximum and minimum MDA concentrations were observed respectively in 20 and 80 mg/l concentration of chloride in Cooker cultivar. Raising chloride concentrations in irrigation water caused a substantial decrease in proline content only in the Kentucky variety.