INFLUENCE OF SOME PRIMING APPROACHES IN REDUCING ADVERSE EFFECTS OF SALT STRESS AT THE GERMINATION, EARLY GROWTH OF SEEDLING, AND GROWTH OF BASIL (Ocimum basilicum L.; Lamiaceae)

Basil (Ocimum basilicum L) is one of the most important under cultivation plants that are broadly used as a medicinal, spice, and culinary plant. In this study, we evaluated the effects of seed priming (distilled water, salicylic acid, potassium nitrate) on the germination characteristics as well as physio-biochemical characteristics of basil plant in ameliorating the adverse effects of saline. In this aim, two distinctive experiments were conducted as a factorial design based on completely randomized design with 2 factors (salt stress and priming) and 3 replications at Ferdowsi University of Mashhad. In the term of salinity and priming effects upon the germination characteristics, the results indicated that all of studied traits are significantly affected by salt stress. Under conditions of salinity, all of the used seed priming agents improved germination percentage, germination rate, and germination average time, especially salicylic acid that improved germination rate better than other priming agents. Seedling length, the fresh weight of seedling, and seedling vigor index were effectively enhanced by potassium nitrate. The results from studying the influences of saline and priming at the basil growth showed that relative water content was high in plants which their seeds treated with potassium nitrate and chlorophyll content was about enhanced when plant seeds treated with salicylic acid. The salicylic acid and potassium nitrated did not show a significant effect on total phenol and antioxidant activity compared to unprimed seeds, although both of which significantly increased under salt stress in unprimed and hydroprimed ones. Collectively, our results suggested that different approaches of priming had positive effects in improving growth parameters of basil under salt stress at germination, early growth stage of seedling, and the seedling growth.