Seed priming with salicylic acid on plant growth and essential oil composition in basil (Ocimum basilicum L.) plants grown under water stress conditions

•The impacts of salicylic acid priming at different harvest were reported for the first time.•Mineral content of the basil was adversely affected with stress, but improved in primed plants.•Both stress and priming enhanced phenolic content and 1,1-diphenyl-2-picrylhydrazyl free scavenging activities.•Both stress and priming did not affect the major essential oil compositions and their percentages. Water stress is of the major abiotic stress factors shifting the plant metabolism and subsequently plant growth, development and yield. In order to reduce the adverse impacts of water stress, herewith the study, the effects of salicylic acid priming on water stressed basil plants has been evaluated through physiological, biochemical and yield parameters. In this context, basil seeds (Ocimum basilicum) were initially primed with 0.05 and 0.1 mM concentration of salicylic acid (SA) and subsequently, basil plants were grown under well-watered and drought conditions. Accordingly, SA priming increased relative water content, water potential, quantum yield (Fv/Fm ratio), shoot height, stem diameter, dry weight, branch number, and leaf number. Furthermore, according to the regression analysis all variables were found to be significant by the t-test for contents of elements. However, interaction of water priming, field capacity and harvesting time was not significant regarding potassium content. According to the standardized regression coefficient (β), of the independent variables, field capacity was more influential factor on the all element accumulation but iron content and it was found to be at the first order in terms of relative importance on the content of elements and then followed by SA priming and harvest time. The content of elements, except Ca and Mg, were reduced with water stress but priming with SA increased the content of the elements. In addition, water stress and SA priming yielded higher contents of phenolic and flavonoid content coupled with higher antioxidant activities. Herewith the study, 1,8-cineol, linalool, eugenol and α-bergamotene were identified as the major essential oil components in all applications. However, treatments did not affect significantly their percentage.