Effect of Salicylic Acid on Antioxidant Enzyms of Milk Thistle (Silybum marianum) Accelerated Aging Seed

Effects of accelerated aging and seed priming treatments were studied on milk thistle seeds during germination process. Experiment was performed in a factorial based on Complete Randomized Design (CRD). Treatments were Salicylic acid concentrations (0, 500, 1000, 1500 and 2000 ppm) and accelerated aging for (0, 48, 96 and 144 hours under 45 °C and 95% humidity) with three replications. Our results showed thatsalicylic acid dramatically enhanced seed germination, seed vigor and primary seedling growth. Catalase, polyphenol oxidase and peroxidase activity was increased by seed priming. Reduction in germination parameters were observed by increase in accelerated aging durations The highest antioxidant activity, germination percentage and daily germination rate and seed vigour were observed at primed seeds with 1000 ppm Salycilic acid on non-aged seeds. Treatment salicylic acid at a concentration of 1000 ppm has the greatest impact and cause harmful effects healing was aging.