Improvement of morphological, physiological, and antioxidant potential in purple basil (Ocimum basilicum L.) through exogenous treatments of salicylic acid and jasmonic acid

The effects of exogenous jasmonic acid (JA) and salicylic acid (SA) treatments on purple basil, which is used in the food industry and traditional medicine for its aromatic properties, were investigated. Purple basil (Ocimum basilicum L.) seeds were sown in pots containing peat moss and germinated in a plant growth chamber at 25 ± 2 °C, under a photoperiod of 16 hours light/8 hours dark, at a light intensity of 27 μmol m−2s−1, and at 45 ± 5% humidity. When the seedlings reached the two-leaf stage, different concentrations (0, 0.5, and 1 mM) of SA and/or JA were treated foliarly. Fifteen days after the second application, the seedlings were harvested. Morphological measurements (root-shoot length, fresh and dry weight) and physiological-biochemical analyses were performed. Root-shoot length, fresh and dry weights, photosynthetic pigment, anthocyanin, and total phenolic content, along with 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, phenylalanine ammonia-lyase (PAL), and catalase (CAT) enzyme activities, increased in all treatment groups compared to the control, while total protein content decreased. It was determined that exogenously treated SA and JA elicitors positively affected the increase in morphological and physiological parameters, as well as the antioxidant potential, in purple basil.