Figure 4

Cumulative seed germination of six Caragana species under gibberellic acid treatments. Seeds of species from arid (C. korshinskii, ●), semiarid (C. intermedia, ⚬, and C. microphylla, ■), semihumid (Caragana arborescens, □, and C. boisi, △), and humid (C. stipitata, ▽) habitats incubated with gibberellic acid (GA₃) concentrations of 0 μg g⁻¹ (a), 100 μg g⁻¹ (b), 250 μg g⁻¹ (c), 500 μg g⁻¹ (d), 1000 μg g⁻¹ (e), 1500 μg g⁻¹ (f), 2500 μg g⁻¹ (g) at 20/10 °C. The seed coat of C. boisi and C. stipitata was cracked. Data are means ± one SE of the mean of the final germination percentage when larger than the symbol (n = 5); the lines are the fitted logistic curve (see Methods).