The effect of seed-priming on germination indices and photosynthetic and carotenoids pigments of summer savory under calcium chloride stress condition

Germination is an important step in seedling establishment and plays a key role in plant production. Environmental stresses such as salinity are a serious threat to the production of agriculture products, yield and active ingredients of medicinal plants. This experiment was conducted to investigate the effects of seed priming on germination parameters of Satureja hortensis under calcium chloride salinity stress (control, 40, 80 and 120 mM). The experiment was conducted in a completely randomized design (CRD) with a factorial arrangement. The pre-primings including control, hydro-priming, KNO3 with concentration of 0.3 Percent and GA3 with concentration of 500 ppm for 12 hours at temperature below 15 °C was carried out. The best homogeneity of time germination, the highest fresh weight and dry weight of the Satureja plant were observed in primed with KNO3. Hydro-priming treatment had the best germination rate and germ velocity coefficient. By increasing the salinity treatment up 120 mM, the germination time was delayed to 4.62 days and the germination rate decreased to 0.22 g per day and no produced the normal seedling. Generally, the reducing in plant growth and content of photosynthetic pigments and carotenoid pigments such as chlorophyll of leaf seedlings occurred at high salinity levels (80 mM up) happened. Therefore, based on the present study, we can uses seed pre-treatment with potassium nitrate or gibberellic acid to increase plant tolerance to salinity in step germination and seedling establishment.