GERMINATION ECOLOGY OF THE ENDANGERED GRASSLAND BIENNIAL GENTIANELLA-CAMPESTRIS

The germination ecology of the endangered biennial grassland forb Gentianella campestris was studied. The seeds had a primary dormancy which was overcome by cold-stratification. Seeds buried in the soil became germinable in early spring (February), and autumn-sown seeds germinated during a four-week period in late spring (May). Exhumed seeds germinated in both light and darkness and in situ germination occurred even at 15 cm depth in the soil. No persistent soil seed bank could be detected in populations of G. campestris, and very few experimentally buried seeds were viable after 21 months in the soil. Together, these results indicate that the species has a transient seed bank, in which case yearly seed production is important for maintaining populations and preventing local extinction.