Bibee, Katherine , Shishido, Katie , Hathaway, Ron , Heschel, Shane .
Population Differentiation in Impatiens capensis at the Range Limits.
For plants occupying a large geographic range the ability to survive in a variety of environments is imperative. As an herbaceous annual that lacks a thick cuticle, Impatiens capensis prefers moist environments and is easily susceptible to drought (Heschel et. al., 2002). Yet, I. capensis grows from the east coast of North America to the Colorado Rocky Mountains. Impatiens growing at the western range limit must endure a much different environment than their eastern relatives. Three large environmental differences between the eastern and western limits of the I. capensis range are light intensity, temperature, soil moisture, and relative humidity (M.S. Heschel, unpublished data). In response to relatively dry conditions, eastern populations of I. capensis have evolved a greater sensitivity to abscisic acid (Heschel & Hausmann, 2001); increased abscisic acid sensitivity results in higher water-use efficiency (WUE) under drought conditions relative to populations from moist environments (Heschel et. al., 2002). These previous studies have compared I. capensis populations within a small region. This experiment addresses the question of how this species deals with stress at the range limit. Specifically, how has I. capensis adjusted to the Colorado climate? Do Colorado plants differ morphologically from Rhode Island or Illinois plants? Do Colorado I. capensis populations react differently to shade and sun treatments than eastern I. capensis populations?
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1 - Colorado College, Biology, 14 E. Cache La Poudre St., Colorado Springs, CO, 80903, USA
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM