copper effects on growth, lipid peroxidation, and total ‎phenolic content of rosemary leaves under salinity stress

plant growth is often limited by low levels of soil micronutrients such as copper (cu), ‎especially in calcareous salt-affected soils of arid and semiarid regions. the aim of this ‎work was to investigate individual and combined effects of salinity and cu on growth, leaf ‎relative water content (lrwc), cell membrane permeability, lipid peroxidation, and total ‎phenolic content (tpc) of rosemary (rosmarinus officinalis l.) in a hydroponic ‎experiment. a factorial arranged experiment with three salinity levels (i.e., 0, 50, and 100 ‎mm nacl), and three levels of copper (i.e., 0, 0.5, and 1.0 µm cu2+, as cuso4) was ‎performed. the salt stress led to a significant decrease in leaf relative water content ‎especially at 0 µm cu2+. salt treatments (50 and 100 mm) were found to increase ‎electrolyte leakage and malonyldialdehyde content of rosemary; however, this increase ‎was greater at 0 µm than 1.0 µm cu2+. regardless of cu treatments, salinity (50 and 100 ‎mm) induced significant increases in tpc by 13 and 29%, respectively. the application of ‎‎1.0 m cu at the 50 mm nacl treatments increased total phenolic content by 19% ‎compared to 0m cu. copper nutrition resulted in greater accumulation of phenolic ‎compounds in plant roots and thereby decreasing lipid peroxidation under salt stress ‎conditions.‎