Cell and Tissue Journal

Abstract Aim: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.
Material and Methods: 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.
Results: 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.
Conclusion: Due to induction of oxidative stress, lead was caused an increase in antioxidant enzymes activity and the content of malondialdehyde, alkaloid and proline.

Abstract Aim:The effects of different concentrations of ZnO nanoparticles on some growth parameters, the amounts of proline and alkaloids and changes in activity of some antioxidant enzymes were investigated. Material and methods: Experiments were performed under controled greenhouse conditions and completely randomized design with three replications. Plants were exposed to different concentrations (2, 4, 5, 10 and 15 mM) of nano zinc oxideand the effect of these concentrations were compared with the plants that used a complete nutrient solution containing zinc Sulfate. Results: Treatment of the plant with concentration of 0 to 2 micromolar caused increased and higher concentrations significantly reduced dry weight as well as root length. The results showed that the antioxidant enzymes activities in the treated plants increased with increasing concentration of nano zinc oxidein the nutrient solution compared to the control plants. As the level of stress was elevated, the amount of proline and total alkaloids also increased. Conclusion: With increasing concentrations of zinc oxide nanoparticles, Zn absorptionraised. Due to this toxicity, plant growth parameters were affected and oxidative stress in plants was induced. To overcome free radical production, plants have increased their antioxidant enzyme activities and proline.