Figure 3.

Germination (a) and cotyledon emergence (b) after three different cold stratification treatments (14, 20, 33 weeks at 5 °C). Seeds were maintained at 5 °C for 14 weeks (closed squares) or 20 weeks (closed diamonds) followed by transfer to two warmer temperatures: 10 °C (solid line) or 15/5 °C (dashed line). Differences in final germination between the control (seeds held at 5 °C for the full 33 weeks of the experiment) and treatments were tested using generalised mixed models with logit‐link function. ***(P < 0.001) and **(P < 0.01) signify treatments that are significantly different from the control (5 °C, open circles). Cold stratification for 0 weeks (i.e. germination temperatures of 10 and 15/5 °C) and for 6 weeks resulted in no germination.