Spearmint (Mentha spicata L.) has several known names, such as garden mint, common mint, lamb mint, and mackerel mint. Salinity is considerably one of the most vital causes negatively affecting plant life, reducing productivity. Kinetin, a cytokinin-like synthetic plant hormone, can promote plant growth against salinity. The potential research sought to study seeds soaking and foliar application of kinetin to mitigate harmful salinity effects, which cause chemo-physiological variations in spearmint due to increased salinity in the irrigation water. In the experiment, two salt concentrations (2.3 dS m^-1 and 6.2 dS m^-1) helped develop the salinity environment, with kinetin (5 mg/L) used for seeds’ soaking for four hours and as an exogenous treatment by foliar spraying of the spearmint seedlings. The results revealed an increased electron leakage percentage (ELP) related to a rise in salinity elements (Na⁺ and Cl^–) at 6.2 dS m^-1 in both groups with reducing K⁺ levels. Likewise, a reduction was prominent in salinity elements with an enhancement in K⁺ level with foliar application than the seeds soaked with kinetin. Increased proline content, H₂O₂, MDA, and an increase in antioxidant activity of CAT and SOD were evident in salinity treatment, which declined by treating with kinetin (5 mg L^-1) foliar application. The results proved that kinetin foliar spraying is the best in supporting Mentha spicata L. plant versus kinetin seeds soaking against the adverse effects of salinity.

Keywords: Spearmint (Mentha spicata L.), salinity levels, kinetin, antioxidant, chemical changes, seeds soaking, foliar spray

Key findings: Using kinetin with foliar spray was superior to soaking seeds with it to promote Mentha spicata L. plants for reducing salt elements Na⁺, Cl^–, MDA, ELP, and proline content with increased K⁺ content and antioxidant active.