Seed germination and conservation of endemic species from the Central Apennines

Seed germination is a critical stage for the establishment of plants as its success is determinant for plant species propagation (Rajjou et al., 2012; Annu. Rev. Plant Biol. 63:507-33). Each species has specific requirements for seed germination (Schütz and Milberg, 1997; Oikos 78: 420-428) which involves particular features of seed and environmental factors. Several germination traits have been claimed to be specific to high-altitude species (i.e. rapid onset of germination after snowmelt and high seed viability). Endemic species are a significant feature of high mountain Mediterranean climate which are one of the most threatened systems in Europe. Many efforts should be addressed to improve the conservation strategies for Mediterranean mountain species considering that the survival of endemic and threatened species is based on different and complementary conservation approaches and techniques. The definition of germination protocols, in particular for species characterized by small populations and for which data are missing, could be an important step in this direction. The objective of this research was to analyze seed germination capability of two endemic species of the Central Apennines included in the Regional Red List: Aquilegia magellensis and Campanula fragilis subsp. cavolinii. Freshly-matured seeds of the considered species were collected from small wild populations growing on Mount Majella (Italy). Debeaujon and Koornneef (2000; Plant Physiol. 122: 415-424) show the role of gibberellins in promoting seed germination. Exogenous application of gibberelic acid (GA3) overcomes seed dormancy in several species. Accordingly, the following treatments were carried out for the considered seed types: control treatment (0 ppm GA3 treatment); 250 ppm GA3 treatment; 500 ppm GA3 treatment; cold-wet stratification treatment. The results show significant differences in germination rate between the species. The treatment with 500 ppm GA3 has a significant effect on A. magellensis germination rate. The cold-wet stratification treatment increases germination in A. magellensis and decreases it in C. fragilis. The observed differences in seed dormancy may be also related to the seed coat thickness. On the whole our results highlight the importance of the selected treatments to favor germination capability and may be used for a protocol in reinforcement projects of the wild populations as a means of reducing the extinction risk.