Study of Dormancy Type and Effect of Different Pre-Sowing Treatments on Seed Germination of Bladder-Senna (Colutea bohsei Boiss.) in Laboratory Conditions

The present study was conducted in order to evaluate the existence and type of the dormancy and effects of different dormancy breaking treatments on seed germination of Colutea buhsei Boiss. (Fabaceae) as one of the Iran native plants, arid-land and ornamental shrub with ability of usage in the urban landscape design. The experiment was performed with 15 treatments and 3 replications in a completely randomized design. Seeds were subjected to different treatments including various levels of GA3, concentrated (98%) H2SO4, cold stratification (CS), soaking with tab water, floating in hot water (100�C) followed by continual cooling for 24 hr in the same water and combined treatments. Afterwards seeds were sown in laboratory conditions to determine the factors� effects on germination percentage (GP), germination rate (GR), root and shoot length of Colutea bohsei seeds. All of these treatments, except for GA3 (250 and 500 ppm), increased the percentage and rate of the seed germination. Maximum germination percentage (66.25%) and rate (14.9 seeds per day) in 7 days was obtained at concentrated (98%) H2SO4 (15 min). Maximum root and shoot length was observed at concentrated (98%) H2SO4 (15 min) plus GA3 (100 ppm, 24 hr). Use of GA3 (100 ppm) in 24 hr after H2SO4 increased the germination rate and shoot length but this additive effect was not significant