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Germination and Early-Seedling Establishment Capacity of Pancratium maritimum L. (Amaryllidaceae) on Coastal Dunes in the North-Western Mediterranean

Abstract There is a scarcity of data on the seedling establishment success of plants inhabiting the sand coasts of the Mediterranean, despite on increasing interest in the conservation and restoration of dune habitats. A field experiment, in conjunction with a series of laboratory germination tests, was conducted to (1) determine the recruitment capacity of Pancratium maritimum, a perennial dune plant which is declining along the north-western Italian coasts, by natural seed dispersal and (2) test the ability of seeds to tolerate different environmental stress. We planted seeds at different burial depths and found that seeds from greater depths (6, 10 and 15 cm) showed higher emergence (35.0–46.6%) than seeds from a shallower depth (2 cm; 11.6%). On average, less than 18% of seeds remained dormant at the end of the germination period. None of the seedlings that emerged in autumn survived over winter, and 88% of those that emerged in spring died by the start of the second reproductive season as a result of desiccation. Therefore, less than 3% of the seeds resulted in established seedlings. Under laboratory conditions seeds germinated well (87.5–100%) in darkness as well as at 12 h alternating light/dark and showed little dormancy (27–35 days). Germinability of seeds remained up to 70% for at last one year of storage. Temperatures below 10°C or over 30°C inhibited germination; frost and heat were lethal for most seeds. Germination was totally inhibited by salinity and water stress. Recovery of germination occurred in seeds from solutions below 25% seawater or −0.6 MPa. These data provide useful information for conservation and reintroduction of this species.