Abstract: Atraphaxis spinosa and A.virgata are native shrubs in Urumqi. The two species are important for the desert ecosystem. Seeds of the species were dormant at maturity. Dormancy break occurred during cold stratification at 5℃ for 8 weeks and 6 weeks, also at the habitat in winter. Seeds stratified at 5℃ and habitat and incubated at 12/12 h daily temperature regimes of 15/6, 20/10, 25/15 and 30/20℃ geminated faster and to a significantly higher percentage at each temperature regime than those not stratified. Seeds of A.spinosa were more deeper dormant than A.virgata. Their seeds were shallow non-deep physiological dormancy.

Key words: Atraphaxis spinosa, A.virgata, seed dormancy, germination, cold stratification, germination phenology