effects of temperature, ga3 and cytokinins on breaking seed dormancy of ferula assa-foetida l

ferula assa-foetida l. (apiaceae) is one of the most important endangered medicinal plants,which is rare in nature due to poor seed germination. in an effort to improve and promote the cultivation ofthis plant, the effects of two temperatures (23°c and 4°c), exogenous ga3 and cytokinins (kinetin and bap)were investigated on dormancy breaking and germination of f. assa-foetida l. seeds. among the treatments,cold stratification (4°c) significantly stimulated seed breaking dormancy. the highest mean germinationindex (2.6 germinated seed per week) was obtained by treatment of seeds with 5 mg/l kinetin at 4°c. but,under no hormone treatment, the highest final percentage germination (73%) was obtained when the seedswere soaked in distilled water and then incubated at 4°c. also, under this condition the germination indexwas achieved to 2.5 germinated seeds per week. treatment of the seeds by ga3 not only could notsignificantly enhance the germination index and percentage at 23°c, but also the existence of ga3 caused amarked decrease in those values at 4°c. this result demonstrated that ga3 was not effective to overcomedormancy for this species.