A laboratory experiment was conducted to investigate the effects of seed priming with salicylic acid (SA) on germination characteristics of ajowan (Carum copticum) under salt stress. The experimental design was completely randomized design with four SA concentrations (0, 0.00001, 0.001 and 10 mM), four salinity stress levels (0, 6, 12 and 18 dS.m-1) and three replications. The seeds were soaked in SA solution for 6 hrs, and after drying, were placed in Petri dishes containing 10 ml of NaCl solution. For 21 days the germination traits were monitored and germination percentage and rate, radicle and plumule lengths and seed vigor were measured. The results showed that salt stress inhibited all of the germination characteristics measured. At high salinity (18 dS/m) all germination traits were reduced to near zero even with SA application. Therefore, under such conditions seed priming of ajowan with SA is not recommended. The 10 mM SA concentration significantly inhibited all the germination traits to almost zero; therefore, it is not recommended for seed priming of ajowan. The 0.00001 mM SA concentration significantly improved all germination characteristics of ajowan up to 12 dS.m-1 salt stress level. Based on the results of this study, seed priming of ajowan with low concentration of SA (0.00001 mM) is recommended under non-saline and up to 12 dS.m-1 salt stress conditions.
