Seed dormancy and germination of five selected NATURA-2000 plant species from Croatia showing different germination strategies

Abstract

NATURA-2000, the ecological network of protected areas in the European Union that has been included in the Croatian legislation, defines Community important plant species with imperative on their conservation ex/in situ. In the Botanical Garden of the Faculty of Science, University of Zagreb, five NATURA-species have been selected as research subjects for germination study to shed light on the topic of their seed ecology and consequently advance their conservation efforts: Degenia velebitica, Scilla litardierei, Klasea lycopifolia, Ligularia sibirica and Genista holopetala. The freshly matured seeds of each species were exposed to cold or warm stratification in duration of four to sixteen weeks, and their germination was investigated through different regimes of incubation parameters, i.e. illumination (light/dark) and temperature (5, 15/6, 23 °C). All species had higher germination values after cold stratification, with the exception of G. holopetala. We concluded that D. velebitica, K. lycopifolia and presumably L. sibirica seeds has non-deep physiological dormancy while S. litardierei has deep complex morphophysiological dormancy and G. holopetala has physical dormancy. The observed patterns in seeds’ behaviour are consistent with the conditions in their natural habitats in Croatia and the knowledge of these patterns is vital for successful conservation strategies in the future.