Limiting temperatures of embryo growth and seed germination of Fraxinus excelsior L. (Oleaceae): a threshold model approach

London

2023

13 S.

Sonderdruck

13192S

40004467

The initial embryo index of mature ash seeds seems to be an individual trait and was not affected by local average annual temperatures. The most effective temperature ranges for embryo growth and germination were similar, however narrow (between 10 and 15 °C). Temperatures above 20 °C inducted secondary dormancy, hampering embryo growth as well as germination. Such a narrow thermal window for embryo growth can potentially act as a limiting factor for the natural regeneration of ash seeds.Keywords: Germination niche, Seeds, Threshold models, Cardinal temperatures, Embryo growth