Dormancy and endosperm presence influence the seed longevity of central European calcareous grassland plants

Despite increasing efforts towards habitat and species protection in Europe since the 1990s, when the Fauna-Flora-Habitat directive was adopted, the proportion of threatened plant species has steadily increased. One strategy to combat this, according to the Global Strategy for Plant Conservation, is to conserve threatened plant species in ex situ collections such as seed gene banks. This strategy strongly depends on seed longevity, with preservation under specific conditions extending seed persistence by hundreds of years. However, not all seeds are the same and detailed knowledge on the longevity of seeds of wild species under genebanking conditions is not well known.

In a recent study published in AoBP, Tausch et al. studied the seed longevity of 39 calcareous grassland species to assess the prospects of ex situ storage of seeds from a single, strongly threatened habitat. The seeds were collected from the Jurassic Mountains of the Franconian Alb in Bavaria, Germany, one of the most species-rich and endangered habitats in Europe. Previous studies have shown that the longevity of seeds from this region is highly variable yet found no correlation with seed oil content or carbohydrate composition. Tausch et al. found that physical dormancy and endosperm absence were generally associated with high longevity whereas physiological dormancy was associated with comparatively short longevity. This confirms previous results of more large-scale geographical studies of seed longevity and contributes to a growing knowledge bank for the management of seed storage facilities.