Effect of salicylic acid on improving morpho-physiological traits of basil under salinity stress

Salinity is one of the most important and common environmental stresses on plants. On the other hand, salicylic acid is effective as a plant growth regulator on inducing mechanisms in plant resistance enhancment against biotic and abiotic stresses. Apot experiment was conducted as factorial based on completely randomized design to evaluate the effect of salicylic acid on improving morpho-physiological indices of basil under salt stress. Seedlings with six to eight leaves were sprayed by salicylic acid at concentrations of 0.1, 0.5 and 1 mM before salinity stress application and continued for three weeks. The salinity stresses were applied by irrigation of plants with saline solutions at concentrations of 20, 40 and 80 mM of sodium chloride. At flowering stage, plant height, stem diameter, leaf length and width, leaf and inflorescence number, leaf, stem, and root fresh and dry weight, the longest inflorescence and root and internode length, stem node number, leaf, stemç and root dry weight percentage, leaf electrolyte leakage, relative humidity, leaf chlorophyll index, leaf area indexç and special leaf area were measured. Salinity stress reduced leaf length and width, leaf area index, branch nodes number, stem diameter, root fresh and dry weight, stem dry weight, special leaf area and increased leaf electrolyte leakage and leaf number. In contrast, using salicylic acid was effective in reducing of the adverse impacts of salinity stress in most of the traits. Also, salicylic acid spraying had more compensatory effect on salinity stress at concentrations of 0.1 and 0.5 mM. Therefore, salicylic acid spraying can be recommended as a contsructive approach to prevent adverse impacts in basil under salinity stress conditions.