Seed Germination protocols for seven Mediterranean taxa of the genus Anthemis (Asteraceae) from Sicily

In this study, we characterize the germination behaviour of seven closely related taxa within the genus Anthemis, with respect to temperature, light, and cypsela morph. The study taxa are Anthemis aeolica, A. aetnensis, A. cretica subsp. messanensis, A. cupaniana, A. maritima subsp. maritima, A. parlatoreana, and A. pignattiorum, all native or endemic to Sicily. The species selected are representative of both lowland and mountain habitats. Seeds were collected from wild populations, at the time of natural dispersal. All of the species possess heteromorphic cypselas with different size, shape, surface ornamentation, and colour. For all of the taxa, two cypsela morphs were identified and tested separately: cypselas with thin and light-coloured pericarp and cypselas with thick and dark-coloured pericarp. Germination was tested in fresh and after-ripened cypselas. Seven constant and, only for A. aeolica, four alternating temperatures were applied both in light and total darkness. The best germination protocols for each seed accession are provided. Fresh light-coloured cypselas reached optimal germination at temperatures ranging from 10 to 20°C. This seed morph both widened its thermal range for germination and increased the final germination percentage following one to three months of after-ripening, showing to possess non-deep physiological dormancy. Dark cypselas showed low germination under any temperature and light conditions, suggesting the presence of a deeper degree of physiological dormancy. However, the role of the pericarp has to be better assessed.