Seasonal changes of antioxidant enzymes activities, water and osmolyte in four halophyte species

Seasonal changes in antioxidant enzymes activities, amount of water, ash, proline and soluble sugars were surveyed during this research in four halophyte species of Varamin County, Tehran, Iran: Salsola turcomanica Litwin, Suaeda arcuata Bunge, Tamarix leptopetala Bunge and Cressa cretica L. Plants were collected randomly from their natural habitats in spring and summer. Activity of these enzymes in response to environmental stresses such as salinity increased in shoots of most species from spring (May) to summer (Aug). In T. leptopetala catalase and ascorbate peroxidase activities were high while peroxidase activity was low in comparison to other species. Peroxidase activity in the other three species and catalase activity in all species were high. Thus, high activity of one antioxidant enzyme in stress condition may be accompanied by the low activity of other enzymes. According to this research, water amount in S. arcuata and S. turcomanica shoots were high and by the increase of salinity water potential reduced. The amount of ash in shoots and roots of all species increased from spring to summer but it was the most in S. arcuata and S. turcomanica. This could be the result of ion accumulation (especially Na+ and Cl-) in salinity condition in these two species. The amount of proline and especially soluble carbohydrates increased in shoots and roots of most species from May to Aug and it was the most in Tamarix and Suaeda.