Figure 5. Shifts in distribution of base water potential of progeny seeds from two Amoronthus polmeri populations (California and Kansas) grown under contrasting maternal water conditions (continuous̜ ̜ ̹ water-deficit ̹ vs. well-watered). Seed germination was tested at two temperatures (20 and 30 C) under five water potentials. A hydrotime model, ̜ ̹ θ Equation 3, g w,t¼ Φ w ― H w,σ, was fit to estimate the median base water potentials, w (vertical dashed lines), and their respective standard deviations, σ, g tg bð50Þ wb bð50Þ wb to produce these probability density curves of normal distribution (see Table 1 for parameter estimates). Note that the area under the curve for base water potential values>0 indicates the proportion of seeds that have not germinated (i.e., dormancy level).