Iranian Journal of Seed Research

In order to investigate the effects of priming with a KH2Po4 solution on emergence and heterotrophic growth of black cumin (Nigella sativa L.) seedling, a series of experiments were conducted at the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in 2013 and 2014. A field experiment was conducted as factorial layout based on a randomized complete block design with four replications. The fertilizer resources (vermicompost (V)+Tiobacilus (T), micronized Sulfur (S)+T, V+S+T and control) and three levels of phosphorus (0, 30 and 60 kg.ha-1) were the first and second experimental factors, respectively. In the second experiment, selected treatments (in which showed emergence below 60% in the previous experiment) and seed priming (no priming, hydro priming and three levels of phosphorus (P)-priming as 100, 300 and 500 mM KH2Po4) were the first and second experimental treatments, respectively. Based on the results, the resources of soil amendment (V+T and V+S+T) significantly increased the emergence percentage of black seed (by 50 and 54%, respectively). In addition, seed reserve depletion percentage, seed reserve utilization efficiency and emergence percentage significantly increased by 300 mM KH2PO4 (by 9, 143 and 29%, respectively). There was a significant positive relationship between the weight of mobilized seed P and the emergence percentage of black seeds (R2= 0.90 **).

Seeds of seven species of medicinal plants collected from the natural habitat in Lorestan province in summer 2011. Germination test carried out in a completely randomized design with four replications of 25 seeds in H2O. Species of Smyrnium cordifrolium, Kelussia odoratissima, Dorema aucheri and Ferulago angulata had no germination while Heracleum persicum, Bunium luristanicum and Falcaria vulgaris showed germination of 30, 96 and 97% respectively. Different treatments of breaking dormancy applied to the species with germination below 30% [moist-chilling for periods of 2, 4, 6, 8, 10 and 12 weeks, with two concentrations of 250 and 500 ppm of gibberellic acid, a combination treatment (gibberellic 250 ppm + 4 weeks moist-chilling and gibberellic acid 500 ppm + moist-chilling for 4 weeks) and potassium nitrate 2 g/l]. The results showed that moist-chilling was the most effective treatments to break seed dormancy of Heracleum persicum (6 weeks), Dorema aucheri (12 weeks), Kelussia odoratissima (12 weeks) and Ferulago angulata (12 weeks). Therefore, based on their reactions to the treatments, dormancy of Kelussia odoratissima and Ferulago angulata could be classified as deep physiological dormancy and species of Dorema aucheri and Heracleum persicum intermediate physiological dormancy type.

In order to study the seed germination behavior and dormancy breaking methods of three weed species (i.e., Chenopodium album, Convolvulus arvensis and Setariaviridis) of pistachio orchards in Rafsanjan, Iran, three separate factorial experiments (with 2 factors) were conducted based on a completely randomized design with four replications, at the Faculty of Agriculture, Vali-E-Asr University of Rafsanjan, Iran, in 2014. Weed seeds were collected from five different regions of Rafsanjan, such as Markazi, Anar, Koshkoiyeh, Kabotarkhan and Nogh. Dormancy breaking treatments for Chenopodium album involved distilled water (control), KNO₃ (at 500 and 1000 ppm), chemical scarification by sulfuric acid (for 5 and 10 min), and cold stratification (for 1, 3 and 5 weeks). Treatments for Convolvulus arvensis involved distilled water (control), scarification by sandpaper, chemical scarification by sulfuric acid (20 and 30 min), and boiling water (for 15 and 30 min). Treatments for Setaria viridis involved distilled water (control), gibberellic acid (250, 500 and 1000 ppm), KNO₃ (500 and 1000 ppm), and cold stratification (for 1, 3 and 5 weeks). The results showed that seed germination percentage (SGP) and mean germination time (MGT) of three weed species were significantly different among weed populations and dormancy breaking methods. For Chenopodium album, cold stratification of 5 weeks resulted in highest SGP (97%) in Nogh population. For Convolvulus arvensis and Setaria viridis, the highest SGP was obtained after scarification by sandpaper (98% in Kabotarkhan population) and using 1000 ppm gibberellic acid (60% in Kabotarkhan population), respectively. In addition, increasing the weight of 1000 seeds in the three weed species in question increased SGP.