Effect of chemical treatments, pre-moist chilling, hot and tap water on seed dormancy breaking in Arctium lappa

Arctium lappa is a medicinal plant of Asteraceae. To break dormancy and increase the germination of its seeds، various methods was tested including KNO3 (0. 2% for 48 h.)، H2SO4 (75% for 5 and 10 min.)، hot water (70 and 90 °C، each for 15 min.)، and tap water (for 24 and 48 h.). Results revealed that the treatment with KNO3 was more effective، yielding 85% germination. On the other hand، treatments with H2SO4، hot (70°C) and tap water also exhibited considerable effects on the germination rate and percentage (in turn- 66%، 65% and 24%). Overall، according to the obtained results and with regard to the negative effect of H2SO4 on the consequential growth of seedlings، KNO3 (0. 2% for 48 h.) and hot water (70°C) would be suggested as the most efficient treatments to break seed dormancy of Arctium lappa.