Physiological dormancy in seeds of tropical montane woody species in Hawai'i

Worldwide, there is relatively little information on seed dormancy and germination of tropical montane species. Our aim was to help fill this knowledge gap by conducting seed dormancy/germination studies on woody species from this vegetation zone in Hawai`i. All species had water-permeable seeds with a fully developed embryo. Seeds of 29 species (23 genera) were incubated in light/dark at 15/6, 20/10 and 25/15 degrees C and germination monitored at 2-week intervals for 16-128 weeks. Seeds ofChenopodium oahuense,Dubautia menziesiiandSilene lanceolatawere non-dormant (ND) and those of 26 other species had physiological dormancy (PD); 10 of the 26 species had conditional PD. The optimum germination temperature regime(s) was (were) 25/15 degrees C, 17 species; 25/10 and 20/10 degrees C, 2; 20/10 degrees C, 6; 20/10 and 15/6 degrees C, 2; and 15/6 degrees C, 2. Worldwide, PD in the woody genera included in our study is more common than ND. In addition to its contribution to the world biogeography of seed dormancy/germination, this study will be useful to conservation biologists who need to germinate seeds of tropical montane species.

Automated summary

This study focused on seed dormancy and germination of woody species in tropical montane regions in Hawaii, revealing that most seeds have physiological dormancy and prefer a temperature regime of 25/15°C for optimal germination. The research indicates that physiological dormancy is more common than non-dormancy in woody genera worldwide.