Exogenous silicium and zinc increase antioxidant enzyme activity and alleviate salt stress in leaves of sunflower

In order to study the effect of salinity stress, silicium nourishment and foliar application of zinc on growth, antioxidant enzyme activity and fatty acid profile of sunflower an experiment was conducted under controlled conditions. The sunflower plants were grown in a hydroponical system and nourished with Hoagland's solution. Silicium was added to Hoagland's solution at three levels: 0, 1 and 2 mM. Furthermore, salinity stress was induced by NaCl solution at three levels: 0, 100 and 200 mM. Zinc foliar application was performed at two levels: 0 and 0.04%. The results demonstrated that salinity stress significantly increased antioxidant enzyme activity, proline accumulation and oleic and linoleic acid while decreased weight of plants, chlorophyll content and euresic acid percentage. Also, silicium application increased fresh and dry weight of plants, proline accumulation and oleic acid but decreased euresic acid percentage. Zinc foliar application increased fresh and dry weight, catalase, superoxide dismutase, glutathione s-transferase activity and proline accumulation. Finally, it can be suggested that silicium application is useful under conditions of salt stress, especially in hydroponical systems.