Seasonal variations in antioxidant components activity and RWC of some plant species in Hormozgan and Southern Kerman provinces

Production of reactive oxygen species (ROS) is one of the effects of drought stress on plants. Plants increase the activity of antioxidant enzymes to counteract the destructive effects (ROS). In this study, the adaptability and drought resistance of three native species of hot and dry regions of southern Iran, including: Taverniera cuneifolia, Lycium shawii and Rhazya stricta as species with soil conservation, forage and medicinal usage capabilities were investigated. Simple random sampling at wet and dry seasons in aerial parts of the mentioned plants in two regions , namely  Rudan in Hormozgan province and Jiroft in the south of Kerman province was done. The variables of relative leaf water content (RWC), catalase, peroxidase and ascorbate peroxidase were measured in the laboratory using the extraction method. The mean values ​​observed were tested at 95% confidence level. The results of comparing the mean between dry and wet seasons showed that the relative water content of leaves of all three species decreases in dry season. However, this decrease was not significant and the plants were able to retain moisture in hot and dry conditions of dry season. The results showed that the activity of catalase and ascorbate peroxidase enzymes in all three species in the analyzed plant samples in both regions increased significantly in two different regions. Peroxidase activity in R. stricta and L. shawii species increased significantly in both regions and decreased in T. cuneifolia species. In general, these three species are adapted as native species in arid regions of the south of the country against drought stresswhen the activity of oxidative enzymes increased. These plants can be used as drought-resistant ones in projects to rehabilitate and benefit the vegetation of the regions in southern Iran desert.