An Investigation of Environmental Factors and Plant Growth Regulators Effect on Dormancy Breaking and Stimulation of Germination in Datura (Datura stramonium L.) Seeds

To study the effect of some varying treatments including such environmental factors as temperature, moisture, and light as well as plant growth regulators on breaking dormancy of Datura stramonium L. seeds, several experiments were conducted. Seeds of Datura stramonium L. possess full dormancy immediately following harvest. Storing the seeds for 3 months (15 Dec. 2005 to 15 March 2006) at room temperature (23±2?C), in refrigeration (5±2?C) and in natural environmental conditions in soil, resulted in an increase in germination up to 48, 56 and 68.5% respectively. Mechanical scarification of the seeds was followed by an increase in germination. The percentage of germination following mechanical scarification for seed one week past their harvest from maternal plants, was nearly 28.5 %, however, for seeds which were stored for 70 days at 5±2?C germination was 75.5%. Plant growth regulators Gibberelin and Kinitin had a significant effect on germination (p<0.05). The highest percentage of germination (28%) was obtained from seeds treated with Gibberelin (400 ppm). Based on the obtained results, it becomes evident that immature embryo, physiological as well as physical factors considerably affect Datura stramonium L. dormancy