Ferula pseudalliacea (Hangawan), a perennial plant of the Apiaceae family, is a rich source of bioactive secondary metab olites, including sulfur-containing compounds and terpenoids, with notable medicinal properties. However, the role of γ-aminobutyric acid (GABA) and melatonin in regulating their physiological, biochemical, and hytochemical responses to salt stress remains unclear. This study investigated the effects of 1.5 mM GABA and 5.0 μM melatonin on F. pseudalliacea seedlings grown in vitro under NaCl-induced stress (0 and 100.0 mM). The results showed that salinity significantly reduced fresh and dry weight, root and shoot length, photosynthetic pigments, relative water content, and key terpenoid phytochemi cals (τ-cadinol and alloaromadendrene), while increasing oxidative stress markers (H2O2 and malondialdehyde), osmolytes (proline), and certain essential oil components (α-bulnesene and γ-muurolene). GABA and melatonin treatments significantly decreased oxidative damage by modulating SOD and POX enzyme activity, enhancing osmolytes accumulation (proline, soluble sugars, and soluble proteins), and improving total antioxidant capacity (DPPH assay). In addition, both treatments increased total phenolic, flavonoid, and essential oil content. These findings revealed the potential of GABA and melatonin to enhance salt tolerance, promote growth, and stimulate bioactive compound production in F. pseudalliacea under in vitro saline conditions. Further studies are needed to validate these effects in field conditions.
