حدیث حسن بیگی

In order to investigate the pre-harvest and priming application effects of gibberellic acid, salicylic acid and nitrogen on seed germination indices of Echinacea purpurea, this experiment was designed on factorial experiment in base completely randomized design with three replications at 2018 in field conditions and laboratory in the department of horticultural science of Ilam University. Experimental factors included gibberellic acid at two concentrations (100 and 200 mg/L), salicylic acid at two concentrations (100 and 200 mg/L) and nitrogen (from urea sorce) at two concentrations (3 and 6 g/L) that were investigated separately and in combination with each other. Treatments were applied with control samples as pre-planting (before maturity and seed harvesting) and seed priming (after seed harvesting). The results showed that the highest germination percentage, vigor index and shoot length were obtained in pre-harvest interaction with gibberellic acid 200 mg/L and nitrogen 6 g/L. The highest germination rate was observed in gibberellic acid 200 mg/L and the highest seed dry weight was obtained in gibberellic acid 100 mg/L. The highest root length was observed in pre-harvest treatment with 200 mg/L of gibberellic acid and 200 mg/L of salicylic acid. Also, pre-harvest nitrogen treatment had significantly higher germination percentage, germination rate, vigor index, shoot length and dry weight than their priming. Therefore, in present study, preharvest treatments of gibberellic acid in combination with nitrogen or salicylic acid were introduced for improving the seed germination of Echinacea purpurea.

To investigate the effects of foliar application of gibberellic acid (GA3) and salicylic acid (SA) on the morphophysiological, biochemical, and yield characteristics of Echinacea purpurea (L.) Moench, an experiment began as a factorial in a randomized complete blocks design with three replications at the research farm of Agriculture Faculty, Ilam University, Iran, by sowing the plants in 2018 and continued by evaluating the plant characteristics for the two consecutive years (2018 & 2019). The experimental treatments included the foliar spray of plants during vegetative growth period with GA3 (0, 100, and 200 ppm) and SA (0, 100, and 200 ppm) as well as their combinations. The results showed that the highest plant height, number of flowers, and fresh and dry weight of the plants (in both years) were obtained in the GA3-200 ppm treatment and the highest amount of total chlorophyll and carotenoids (in both years) in the GA3-100 ppm one. The highest capitol diameter and fresh and dry weight of flowers in the first year and the highest anthocyanins content in the second year were observed in the GA3-200 ppm treatment. Also, the highest capitol diameter in the second year and the highest anthocyanins content in the first year were obtained in the SA-100 ppm treatment. In addition, the highest fresh and dry weight of flowers in the second year was recorded in the SA-200 ppm treatment. The highest essential oil amount of flowers, shoots (without flowers), and total essential oil (in both years) were obtained in the GA3-100 ppm+SA-100 ppm combination treatment. Considering that increasing the plant dry matter yield as well as essential oil content were the most important objectives of this study, the GA3-200 ppm treatment for the plant dry weight increase and the GA3-100 ppm+SA-100 ppm combination treatment for the essential oil content increase could be suggested as the best treatments.

In order to investigate the possibility of chilling resistance induction and reduce the chilling injury of cucumber seedlings, a factorial experimental based on completely randomized design with three replications was conducted in a greenhouse at Ilam University, Ilam Iran in 2018. The experimental factors were included concentrations of 0, 5, 10 and 15 mM gamma-aminobutric acid (GABA) and two methods of application including seed priming and foliar application at four true leaf stages. Treated plants were incubated at 3 °C for six nights and then investigated for different characteristics. Results showed that all GABA treatments reduced chilling injury in cucumber seedlings. Moreover, although there were no significant differences among the different GABA concentrations for most of the studied characteristics, seed priming was better than foliar application. The lowest chilling index, lipoxygenase activity and highest shoot fresh weight were observed in seed priming application of GABA but with no significant differences among GABA concentrations. The highest shoot dry weight (6.77 and 6.68 g.plant-1), chlorophyll index (20.57 and 21.07 mg.g-1 FW: leaf fresh weight), total protein (1.29 and 1.25 g.kg-1), proline (21.92 and 22.42 μmol.g-1 FW), catalase activity (115.67 and 126.9 U.g-1 FW) peroxidase (0.61 and 0.63 U.g-1 FW) and the lowest ion leakage (30.22 and 29.22 %), malondialdehyde (0.65 and 0.60 μmol.g-1 FW) and hydrogen peroxide (1.27 and 1.19 μmol.g-1 FW), were observed in seed priming application of 10 and 15 mM GABA concentrations, respectively. Therefore, seed priming application of 10 mM GABA is recommended for reducing the chilling injury in cucumber seedlings.