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Randomized factorial design was implemented in four replications to determine optimal methods of Ajwain (Carum capticum) standard seeds germination in SPCRI. Ajwain seeds were placed top and between paper and sand exposed to two potassium nitrate (two grams per 1000 ml distilled water) and pre-chilling (seven days under 7-10ºC) pre-treatments which were under six temperatures (10, 15, 20, 25, 20-30, and 35ºC) in germinator for 25 days so as to germination indices were assessed. Ajwain seeds viability was estimated 75% after tetrazolium test. The highest final and normal seedling percentages were found under 15 and 20ºC in pre-chilling treatment and also 20ºC in potassium nitrate and control. No germination was observed under 35ºC in potassium nitrate and control, however, pre-chilling led to >26% germination. The higher germination potential was shown in top and between papers compared with sand. The lowest germination rate was recorded in control and potassium nitrate and the highest one in pre-chilling. The maximum of seedling weight vigor was suggested in top and between paper when seeds were put under 10, 15, and 20ºC. In order to evaluate optimal standard germination of Ajwain seeds, it was resulted that applying of two potassium nitrate and pre-chilling treatments placed top and between papers under 15 and 20ºC caused maximum of germination potential and seedling weight vigor. [ABSTRACT FROM AUTHOR]

With the aim of evaluating the effect of salicylic acid in improving the efficiency of the aged pumpkin seeds under drought stress conditions, a factorial experiment was carried out in the form of a completely randomized design with three replications. Pretreatment of different concentrations of salicylic acid including zero (pretreated with water), 1 and 1.5 mM at different drought levels of zero, -0.2, -0.4 and -0.6 MPa were investigated. Indicators of mean germination time, germination percentage, seedling length, seed vigor, membrane electrolyte leakage, soluble carbohydrates, soluble proteins, malondialdehyde, ascorbate peroxidase activity, superoxide dismutase and catalase enzymes were evaluated. The results showed that the pretreatment of seeds with different concentrations of salicylic acid prevented the significant decrease in the germination indices of the deteriorated pumpkin seeds under drought stress. So that at the potential of -0.6 MPa, the treatment of seeds with 1.5 mM salicylic acid increased the percentage of germination, seed germination index, soluble carbohydrates and soluble proteins respectively 80.2, 169.4, 51.6, 93.4% and for the activity of ascorbate peroxidase, superoxide dismutase and catalase enzymes, 41.2%, 12% and 11.8%, respectively, compared to the control. Based on the research findings, seed priming with 1.5 mM concentrations of salicylic acid is recommended in order to reduce the oxidative stress caused by drought for pumpkin seeds. [ABSTRACT FROM AUTHOR]