Effect of different levels of salinity on growth indices, mineral absorption, antioxidant enzymes activity and some physiological traits of roots and leaf in GN15 hybrid rootstocks

In order to investigate the effects of different levels of salinity on growth indices, proline and chlorophyll content, nitrogen concentration, potassium, phosphorus and sodium contents of leaf and sodium concentration of root of GN15 hybrid rootstocks, as well as the activity of three antioxidant enzymes, an experiment was conducted based on a completely randomized design with 4 salinity levels of 0, 35, 70 and 105 mg / L sodium chloride and 5 replicates in 1394. Different concentrations of sodium chloride were added to the pots containing these plants and after 100 days of salinity stress, these traits were measured. Results showed as increasing salinity levels, growth indices including plant length and diameter, leaf number and area, relative humidity content and leaf chlorophyll content decreased. This reduction was lower at concentration of 35 mm but was very severe at 105 mM. Concentration and efficiency uptake of nitrogen, potassium and phosphorus decreased with increasing sodium chloride concentrations, and increased the concentration of sodium in leaves and roots and its uptake efficiency in leaves. The amount of proline in the root and leaf increased simultaneously with increasing salt concentrations, so that its amount reached a maximum at concentration of 70 mM (39 and 30 mg / g fresh weight). The activity of antioxidant enzymes was also increased by increasing the salt concentration up to 70 mM, so that SOD, POD and CAT of roots in this treatment were 150.2, 22.6,13 and for leavs were 183.8, 16.8 and 24 U/mg protein, respectively.