Morpho-physiological and biochemical properties of Carum copticum (L.): effects of salicylic acid

Salicylic acid (SA) is a phenolic compound and its foliar application shows regulatory effects on plants. In this research, Ajowan (Carum copticum) plants were treated with 0, 0.5, and 1 mM SA and proline, total phenol, chlorophylls, carotenoids, soluble sugar, N, P, and K contents were studied. Results showed that application of SA affected both quantitative and qualitative traits of Ajowan. The plants treated with SA (0.5 and 1 mM) showed higher plant height, number of umbels per plant, stem diameter, number of branch, number of seed per umbel, seed yield, a thousand kernel weight, and percentage and yield of essential oil compared to control plants. With supplementation of SA and increasing its concentration, total phenol, chlorophylls, carotenoids, and soluble sugar contents were also significantly enhanced. Results also indicated that application of SA significantly improved the amount of macro-element (N, P, and K) in Ajowan compared to untreated plants. In sum, application of SA as a foliar agent resulted in a remarkable change in morpho-physiological and biochemical traits of Ajowan plants.