Storage on Maternal Plants Affects Temperature Requirements during Germination in Rumex obtusifolius

Aerial seed banks facilitate population persistence by extending the temporal range of seed dispersal.  Knowing the temporal range of germination will improve our understanding of the relationship between seed germination dynamics and aerial seed bank storage duration.  We tested the effects of temperature (12/12 h of 5/10, 10/20, 20/30 and 25/35 ◦C) and light variation (12 h light/12 h darkness and 24 h darkness per day) on germination of Rumex obtusifolius L. seeds retained in an aerial seed bank for 0, 2, 4, 6, 8 and 10 months.  Freshly harvested R. obtusifolius were non-dormant and exhibited germination rates of up to 92%.  Overall, seeds of R. obtusifolius germinated reliably at all but the lowest temperature (5/10 ◦C). Seeds maintained high viability throughout the collection period, indicating that fluctuating weather conditions had little influence on seed germination. Thus, the species can maintain viable seeds in aerial storage for up to 10 months and contribute viable seeds to the soil seed bank year-round. This ability to maintain a renewed soil seed bank contributes to the species’ strong resilience in colonizing disturbed areas and makes it a difficult weed to control.