Investigation the effect of lead on the activity of antioxidant enzymes, level of prolin and alkaloid in the callus of Catharantus roseus

Periwinkle (Catharanthus roseus) is a medicinal plant as a result of which its medicinal compounds and alkaloids have been under a great consideration. Lead is one of the most common heavy metal contaminant in the environment. Induction of oxidative stress is a result of the presence of heavy metals in plant cells. Due to the problem of heavy metal pollution and the dangers of pollution to plant in this study, the effects of oxidative stress caused by the presence of lead on activity of antioxidant enzymes, level of prolin and alkaloid in callus grown on MS medium with different concentrations of lead were investigated. Catharanthus roseus seeds were planted in the vase containing Pearlite, then to induce callus, the leaves under the sterile condition were put on the solid MS culture media. Calluses were subcultured after three weeks, the calluses after two subculture were treated with different concentrations of lead nitrate (0, 10 and 50 μM). The activity of antioxidant enzymes and content of proline and alkaloid were assayed. Data analyzed at P ≤ 0.05 level using SPSS software. The results of this study showed that the activity of antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POX), catalase (CAT) and the level of proline and alkaloid as well as lipid peroxidation increased significantly (p<0.05) in comparison to control. Due to induction of oxidative stress, lead was caused an increase in antioxidant enzymes activity and the content of malondialdehyde, alkaloid and proline.