Abstract Detail

Ecological Section

Marshall, Elizabeth [1], Winkler, Katharine [1], Etterson, Julie [1].

Seed characteristics of Schizachyrium scoparium (Poaceae) along geographical gradients.

Climate may play an important role in determining reproductive fitness in plants as expressed in traits such as seed size. Larger seeds tend to produce larger seedlings with higher survival rates and therefore higher fitness. While several studies have shown a negative relationship between seed size and latitude among species, few have analyzed patterns of seed size along geographic gradients among populations within species.  The purpose of our research is to analyze the variation in seed size of Schizachyrium scoparium across latitudinal and longitudinal gradients in the Midwest and eastern United States. In summer 2013, seeds were collected from twelve populations at nine locations spanning both temperature and precipitation gradients. Across this geographic range, temperature increases from north to south and precipitation increases west to east.  Seed size was expected to have a positive relationship with latitude and longitude, and be positively correlated with both temperature and precipitation.  Average seed mass was calculated from a random sample of 5 seeds from 5 random maternal plants per population and analyzed to determine effects of latitude, longitude, and their interaction.  As expected, latitude and seed mass had a positive relationship; however, this depended on longitude.  Midwestern populations show a strong pattern of decreasing seed mass with increasing latitude, while the opposite relationship was observed for eastern populations.  Positive correlations between 30-year minimum (r = 0.49, P < 0.0001) and maximum temperature (r = 0.45, P < 0.001), and precipitation (r = 0.38, P < 0.01) normals suggest that climate may play a role in determining seed size of this species.  If S. scoparium is locally adapted to current climate conditions across its range, climate change could impose selection pressures on traits important to fitness, including seed size.  Project Baseline, a genome bank for the study of plant evolution in response to environmental change, offers a powerful tool for future studies of this nature across species ranges.

Related Links:
Project Baseline website

1 - University Of Minnesota Duluth, Biology, 1035 Kirby Dr, Duluth, MN, 55812, USA

Keywords:
Geographic variation
Seed size
temperature
precipitation.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PEC037
Abstract ID:827
Candidate for Awards:None