Evalution of Arctium lappa seed dormancy breaking methods

Arctium lapp < /em>a is an important medical plant with seed dormancy problem. A study was carried out to investigate the effects of seed dormancy breaking treatments on Arctium lapp < /em>a germination. Treatments were arranged in a completely randomized design (CRD) with five replication. The highest germination percentage was recorded in seeds treated with GA3 (500 ppm) +  H2SO4 75% (86%), GA3 (500 ppm) + hot water 70 0C (87%) and GA3 (500 ppm) + hot water 90 0C (84%). Seed scarification with hot water were better than H2SO4 because H2SO4  increased abnormal seedling percentage. Highest abnormal seedling showed in H2SO4 75%, GA3 (500 ppm) + H2SO4 75% and KNO3 (1%) +  H2SO4 75 % treatments (11.7%, 11.3% and 10.9% respectively). Seed treatment with KNO3 andGA3 increas α- amylase activity and Auxin concentration in Arctium lapp < /em>a seedlings and decreased Abscisic Acid content in seedlings. The maximum seedling vigor index obtaines in seeds treated with GA3 (500 ppm) + hot water 70 0C . Results indicated Arctium lapp < /em>a seeds scarification with hot water 70 0C (10 min) followed by socking in GA3 (500 ppm) for 12 hour was most effective treatment for seed dormancy breaking and improved seedling growth.