Epicotyl physiological dormancy in desiccation-sensitive acorns of <i>Quercus sagrana</i> , a vulnerable endemic species from western Cuba

Most Fagaceae species, particularly those within the dominant genus Quercus , are known to produce desiccation-sensitive (DS) acorns, although this conclusion is based on studies of only a few species. This study characterised the dormancy mechanisms, seed storage behaviour and germination pattern of Quercus sagrana , a vulnerable endemic species from western Cuba and the only Quercus species in the Caribbean region. Acorns collected from two provinces with similar environmental conditions had a moisture content of approximately 37% (fresh weight basis) and achieved 100% germination (radicle emergence) within seven days at 25°C, indicating an absence of physiological dormancy (PD) in the radicle. However, acorns from Province II exhibited delayed shoot emergence after radicle emerged, suggesting PD localised in the epicotyl (subclass 2 epicotyl dormancy). Approximately 22% of acorns showed no delay in shoot emergence. Germination proceeds via radicle extension, followed by development of a swollen structure from which multiple roots establish, with shoot emergence occurring after a delay. Freshly collected acorns stored at room temperature experienced high mortality, and the probability of desiccation sensitivity value exceeds 0.5. Based on these results, we conclude that Q . sagrana produces DS dormant acorns.