Abstract
For many species and seed sources used in restoration activities, specific seed germination requirements are often unknown. Because seed dormancy and germination traits can be constrained by phylogenetic history, related species are often assumed to have similar traits. However, significant variation in these traits is also present within species as a result of adaptation to local climatic conditions. A growing number of studies have attempted to disentangle how phylogeny and climate influence seed dormancy and germination traits, but they have focused primarily on species-level effects, ignoring potential population-level variation. We examined the relationships between phylogeny, climate, and seed dormancy and germination traits for 24 populations of eight native, restoration-relevant forb species found in a wide range of climatic conditions in the Southwest United States. The seeds were exposed to eight temperature and stratification length regimes designed to mimic regional climatic conditions. Phylogenetic relatedness, overall climatic conditions, and temperature conditions at the site were all significantly correlated with final germination response, with significant among-population variation in germination response across incubation treatments for seven of our eight study species. Notably, germination during stratification was significantly predicted by precipitation seasonality and differed significantly among populations for seven species. While previous studies have not examined germination during stratification as a potential trait influencing overall germination response, our results suggest that this trait should be included in germination studies as well as seed sourcing decisions. Results of this study deepen our understanding of the relationships between source climate, species identity, and germination, leading to improved seed sourcing decisions for restorations.
| Original language | English (US) |
|---|---|
| Article number | e0191931 |
| Journal | PloS one |
| Volume | 13 |
| Issue number | 2 |
| DOIs | |
| State | Published - Feb 2018 |
Funding
This research was supported by Northwestern University Graduate Program in Plant Biology and Conservation (www.plantbiology. northwestern.edu) and the Native Plant Society of New Mexico (www.npsnm.org) through grants awarded to AES. Funding was also provided by the Bureau of Land Management’s Plant Conservation Program (grant DBI-0521245; www. greatbasinnpp.org/usdi-blm/) and NSF MRI (grant DBI-1125997; www.nsf.gov/mri/) through grants awarded to Chicago Botanic Garden. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We thank Kayri Havens, Stuart Wagenius, and Jessamine Finch for assistance with experimental design and statistical analyses. Nora Talkington, Rachel Hosna, Alicia Foxx, Maggie Eshleman, and Lila Leatherman helped with seed collection; Kathy See, Patrick Alexander, and Dustin Rooks shared seeds; Jacob Zeldin, Olga Kildisheva, Becky Barak, and Kathy Barton for lab assistance. The Kramer-Havens Lab Group and the Denver Botanic Gardens Research and Conservation department provided helpful feedback on earlier versions of this manuscript.
ASJC Scopus subject areas
- General
