Figure 1

Cumulative germination for Helianthus annuus L var. S1-278 at (a) 15 °C, (b) 20 °C, (c) 25 °C and (d) 30 °C having different water potentials (0, − 0.3, − 0.6, − 0.9 and − 1.2 MPa). Symbols indicate water potential and lines indicate cumulative germination predicted by the hydrothermal time model.