Seed germination regulation and field seed bank carryover in shadscale (Atriplex confertifolia: Chenopodiaceae)

In laboratory germination studies with 15 collections of Atriplex confertifolia, a dominant shrub of North American salt deserts, we found that seeds were dormant and largely unresponsive to chilling at dispersal but became chilling-responsive through dry after-ripening. Collections from warm desert habitats were more chilling-responsive and after-ripened more rapidly than those from cold desert habitats. In a field seed bank experiment, germination did not take place until the second spring, and 30% of the seeds remained viable and ungerminated after five springs. Cold desert collections showed highest seed bank carryover. Spring germination and seed bank carryover across years are important aspects of shadscale life history. (C) 1998 Academic Press Limited.