The pot experiment was carried out as completely randomized design with three replications to investigate the effect of seed priming with potassium nitrate, salicylic acid and distilled water on plant growth, morphological characteristics, physiological and biochemical basil under salt stress in Ferdowsi University of Mashhad. First factor included seed priming with 3% potassium nitrate for 6 hours, 0.5 mM salicylic acid for 12 hours and hydro priming with distilled water for 24 hours and the second factor included values of NaCl solution at three levels (0, 50 and 100 mM). Analysis of variance showed that the interaction of salinity stress and priming on chlorophyll b, carotenoids, antioxidant activity, total phenol, electrolyte leakage, chlorophyll index, relative water content (RWC), inflorescence height, weight of leaves and stems was significant at the 1% level, and on chlorophyll a, total chlorophyll, number of branches, number of flowering branches, the leaves and stem dry weight was significant at the 5% level. The results showed that priming improved morphological characteristics and plant growth especially in non-salinity stress condition. Mean comparison showed the highest amount of total chlorophyll was obtained from plants which the seeds priming with distilled water and were grown in non-salinity stress condition (14.4 mg/g wet weight) and lowest seen in priming with distilled water and 100 mM NaCl stress (4/01 mg/g fresh weight). The highest and lowest total phenol was obtained from plants which the seeds primed with potassium nitrate and were grown in 50 mM and of 100 mM NaCl, respectively. The highest antioxidant activity of leaf extract obtained from plants which the seeds primed with distilled water and were grown in 50 mM NaCl. The highest percentage of electrolyte leakage ofleafwasachieved from plants which seeds treated with sterile water and were grown in 100 mM NaCl. Therefore priming accelerate the germination and early growth of basil and improved biochemical and physiological of plants in salinity stress condition.

Keywords