Seed traits variation and their effects on germination for high altitude mountain species

Endemic species are a significant feature of high mountain Mediterranean climate which are one of the most threatened systems in the European Union. Seed germination capability of Adonis distorta, Androsace mathildae, Aquilegia magellensis and Campanula fragilis subsp. cavolinii (endemic species of Central Apennines and included in the Regional Red List) were studied. Pre-treatments to increase germination rate (250, 500 ppm GA3 treatment, cold-wet stratification treatment) were carried out on seeds collected from the wild populations growing at high altitude on Mount Majella (Italy). The results show significant differences in seed traits and germination rate among the species. Germination does not occur in Ad. distorta and An. mathildae in response to the treatments suggesting that seeds from the highest elevation have a deep physiological dormancy. The treatment with 500 ppm GA3 has a significant effect on germination of Aq. magellensis. The cold-wet stratification treatment increases germination in Aq. magellensis and decreases it in C. fragilis. The observed differences in seed dormancy may be also related to the seed coat thickness which is the largest in Ad. distorta, Aq. magellensis and An. mathildae and the lowest in C. fragilis. Our results underline the importance of the selected treatments to favor seed germination of these endemic species and may be used for a protocol in reinforcement projects of the wild populations as a means of reducing the extinction risk.