Inter- and intraspecific variation in seed germination traits of Arctic plant species
Cold adapted plant species often dependent on seed dormancy breakage for successful germination, yet the effects of climate-driven changes in soil temperature on this process remain unclear. To improve our understanding of temperature impacts on seed dormancy breakage of Arctic plant species and populations, we investigated how different durations of cold-moist stratification at 0 °C or -5 °C affected seed germination of three Greenlandic plant species: Luzula spicata, Juncus trifidus, and Luzula multiflora. Seeds were collected from natural populations at low (0 m a.s.l) and high (500 m a.s.l.) elevations. Germination patterns differed between species, however, in general germination percentages were significantly higher for low elevational seeds compared to high elevational seeds for all three species. Elevation affected day of first germination only in J. trifidus. Stratification temperature, however, affected both day of first germination for J. trifidus and L. multiflora and the germination rate of L. spicata. Several species-specific interactions among stratification duration, elevation, and stratification temperature were identified. These findings show that Arctic plant species, and even their individual populations, exhibit different dormancy patterns. Climate change may thus affect populations and species differently, with important consequences for future Arctic plant community dynamics.