Effect of Some Physical Treatments to Overcome Zarin-giyah (Dracocephalum kotschyi Boiss.) Seed Dormancy

Zarin-giyah (Dracocephalum kotschyi Bioss.) is a medicinal plant and an endemic species in Iran. It is grown and well adapted to high elevations. This plant can be found in some areas such as Tabriz, Yasuj, Mazandaran and Isfahan. Germination in Zarin-giyah seed is irregular and takes a long period of time. This study conducted in 2021-2022, and the potential of Zarin-giyah seed dormancy release was evaluated using eight different treatments which consisted of: scratching with sandpaper, 24 hours of running water + 12 weeks of cooling at 4˚C, 48 hours of running water + 12 weeks of cooling at 4˚C, 60 ˚C hot water for ten minutes, freezing the seeds for 48 hours at -18 ˚C, 24 hours of running water + 48 hours of freezing at -18 ˚C, 24 hours of running water + scratching and the control. The result showed that seedling germination index, root and shoot dry weight, shoot length, mean germination time and germination rate were significant at the 1% probability level. Also, these results showed that using 24 hours of running water and 12 weeks of cooling at 4˚C improved germination traits in Zarin-giyah. Reducing the duration of seed immersion in running water is suggested as a means of achieving better results.