Study of growth and defense response of root sunflower plant under pyrene and phenanthrene stress

PAHs are of the most important environmental pollutants, which enter into the environment from various sources. The presence of these compounds in the soil creates a variety of stresses in plants which is unfavorable for plant growth and development. This study was conducted to evaluate the effect of pyrene and phenanthrene concentrations (50 and 100 mg/l) on germination, growth, accumulation, and induction of oxidative stress in sunflower root. The results showed that increasing the pyrene and phenanthrene concentration reduced root growth indices (fresh and dry weight and root length) but they have no significant effect on germination. On the other hand, the amount of malondialdehyde of the root that is the index of the membrane peroxidation of root cells in both concentrations increased significantly in comparison with the control. This is indicative of oxidative stress