Interactions of amino acids (proline and phenylalanine) and biostimulants (salicylic acid and chitosan) on the growth and essential oil components of savory (Satureja hortensis L.)

Savory (Satureja hortensis) from the Labiatae family contains approximately one percent of essential oils, including compounds such as carvacrol, thymol, paracymen and limonene. This study aimed to investigate the interaction of amino acids and biostimulants with growth indices and phytochemical traits of savory in a factorial experiment as a randomized complete block design with three replications. The first factor, foliar spraying of biostimulants, contained salicylic acid in two concentrations of 0.5 and 1 mM and chitosan 0.1 and 0.5% as well as control (5 treatments). The second factor, amino acids spraying, contained proline and phenylalanine in two concentrations of 1.5 g and 3 g/l and spraying with distilled water as a control (5 treatments). Plant growth indices, percentage and yield of essential oil and active ingredients of essential oil (carvacrol, P-Cymen, α-Pinene and γ-terpinene) were measured. Results indicated that the highest indices of plant growth and percentage of essential oil were observed in the treatments of 1.5 g/l proline. In the treatments of 1.5 g/l of amino acids, chitosan and salicylic acid did not affect the percentage of essential oil, but in higher concentrations (3 g/l), they caused a significant increase in the percentage of essential oil. The highest essential oil yield was obtained in the amino acid treatments in 0.5 mM salicylic acid and chitosan. The highest percentage of carvacrol in the treatments was 1.5 g in liters of proline and phenylalanine, and under these treatments, no significant difference was observed between salicylic acid and chitosan treatments.