Abstarct: Pre-treatment of seeds with ultrasonic wave is one of biophysical seed priming. Continuous ultrasonic wave’s impact increases the penetrability of the seed shell and accelerates the absorption of water and increases the temperature of the tissues. The increase in temperature and rate of seed turgescence in pretreated seeds accompany with accelerated changes in seed germination mextabolism. So, the aim of this study was to investigate the effect of ultrasonic waves on germination, and activity of some germination-related enzymes in purple coneflower seeds. This experiment was carried out in a completely randomized design with 5 treatments and 4 replications in Faculty of Agriculture, Shahrood University of Technology in 2017. Experiment treatments were 5 irradiation durations of 0, 10, 15, 20, and 25 minutes with ultrasonic device. The results of this experiment showed that the effect of irradiation durations was significant on all measured traits. The highest percentage of germination and seedling dry weight was obtained for 15 minutes ultrasonication. The highest amount of R50 and seed reserve utilization efficiency was obtained for 15 and 25 minutes ultra-sonication. Ultrasound waves caused increase alpha-amylase, protease, alcohol dehydrogenase, glucose 6-phosphate dehydrogenase, glutathione reeducates activities, sugars and proteins content in most of irradiation durations compared to control. The best irradiation duration that improved germination properties and biochemical characteristic of germinating purple coneflower seed was 15 minutes. In order to quantify the germination-rate response of purple coneflower to temperature and water potential, the germination response of purple coneflower was investigated under temperature treatments (10, 15, 20, 25, 30 , 35 and 40 ˚C) and water potential (0, -3, -6, and -9 bar) as factorial baxsed on completely randomized design. Results showed that the effect of temperatures, water potentials and their interactions were significant on germination rate and germination percent. Assessing three non-linear regression models including dent like, 2-piece segmented, and original beta indicated the superiority of 2-piece segmented model. The resulted cardinal temperature were the baxse temperature of 17.02 ℃, the optimum temperature of 23.8 ℃ and ceiling temperature of 43.3 ℃, and the biologic hours for germination for potential of zero bar was 84.5 hours. Salicylic acid and jasmonic acid (chemical elicitor) are drawing attention since they as key signaling compounds in induction process lead to the accumulation of secondary mextabolites. Exogenous application of these compounds causes an induction of pseudo stress in plant and excites defensive responses of plant. In response to induction of oxidative stress, the plant increases the amount of antioxidant genes exxpression followed by an enhancement in activity of enzymatic and non-enzymatic anti¬oxidants (they often have a medicinal aspect). The present study was carried out to investigate the effect of salicylic acid and jasmonic acid on enzymes stimulating oxidative stress, defensive enzymes and some secondary mextabolite, yield and yield component of purple coneflower and stevia. This experiment arranged as randomized complete block design with three replications and 12 treatments in Agriculture Faculty of Shahrood University of Technology in 2015-2016. Treatments were spraying the jasmonic acid (ja) with 4 concentrations (0, 5, 20 and 50 micromolar), the salicylic acid (sa) with 3 concentrations (0, 0.5 and 1 milimolar) and spraying both of them three times with 10-day intervals, started at reproductive initiation stage (purple coneflower) and after establishment stage (stevia). The analysis of variance results showed that spraying was effective on all total traits with 99% confidence. The highest amount of NADPH oxidase activity obtained for treatment 20ja-1 sa. The activity of enzymatic antioxidants, including SOD, was increased for most treatments. The non-enzymatic antioxidant contents such as total phenol, flanoid, flanol and anthocyanin increased for most of treatments. These compounds which are phenyl propanoide compounds got increased along with enhanced activity phenylalanine ammonia lyase. The highest amount of phenol was observed for treatment 50 ja with average of 38.8 mg/g.fw. Spraying on stevia caused the decrease in amount of chlorophyll a and b in most treatments compared to control, but carotenoid content was higher in 9 treatments than control. The enzymatic antioxidant activities increased for some treatments. The content of none-enzymatic antioxidants got increased, the phenol content was higher for most treatments, flanol and flanoid contents increased for all treatments. Despite decreasing the amount of chlorophyll content, probably due to increased antioxidant activity, the highest dry leaf weight was obtained for treatments 20ja-0.5 sa, 20 ja-1sa, 50ja- 0.5 sa and 50ja-1sa. The amount of Stevioside and Rebaudioside A was measured for 3 treatments. The highest amount of Rebaudioside A was obtained for treatment 20 ja. The jasmonic acid could make a change in glycosides amounts, and enhance the amount of Rebaudioside A which is the best compound in stevia. Therefore, the application of jasmonic acid is suggested to increase the Rebaudioside A.