Abstract:

Purpose: The study aimed to overcome the seed dormancy of Datura stramonium L. by chemical scarification, pre-chilling, and different gibberellic acid (GA3) levels. Materials and Methods: The seeds were prechilled at 4°C and 10°C for 7 days and treated with sulfuric acid (97-98% H2SO4) for 15 minutes, and increasing doses of GA3 (250, 500, and 1000 ppm). Distilled water for hydration and untreated seeds served as a control. Results: The results showed that no germination was observed in the control and prechilled seeds of Datura stramonium L. The dormancy rate was 100% and the seed dormancy resulted from both hard seed coat and physical dormancy. Mean germination time and germination index of control seeds could not be calculated because no seed germination occurred. Although the chemical scarification showed a beneficial effect for breaking dormancy, the gibberellic acid applications were more effective seed treatments for increasing germination compared to sulfuric acid. The germination percentage increased from 0.0% to 44.5% in the seeds scarified and treated with 1000 ppm GA3, while the germination percentage of primed seeds with 1000 ppm GA3 was 68.5%. Mean germination time was lessened by GA3 doses and scarification. Furthermore, the germination index was promoted by the applications of GA3, especially in the seeds without scarification. The higher germination index was obtained from control seeds under all levels of GA3. The highest shoot length was measured at the highest level of GA3 with 14.6 cm. Conclusion: Seed dormancy can be effectively broken by the application of 1000 ppm GA3 without chemical scarification.

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