Thermal requirements for embryo growth and seed germination of Fraxinus excelsior L. (Oleaceae)

We have examined thermal control for embryo growth and seed germination in European ash. Using data historical data (span of 36 years) of embryo index in matured seeds we showed that maturation is not influenced by the annual average temperature. While embryo growth and germination are controlled by similar temperature range. Our results shows thermal windows for development and germination of ash seeds.