Griffith, Alden B. , Andonian, Krikor , Loik, Michael E. .
Phenotypic plasticity in native and invasive populations of Bromus tectorum.
Phenotypic plasticity has often been considered an important attribute for invasive plant success. However, are invasive plant species inherently plastic, or is plasticity the result of sampling effects and/or evolved plasticity in the introduced range? To explore the latter, we examined the plastic response to temperature for Bromus tectorum populations collected across elevational gradients from areas in both native (Armenia) and invasive ranges (California and Nevada). Seeds were collected from 8 native and 7 invasive populations during the summer of 2006. Plants were grown in a greenhouse common garden during the spring and summer of 2007 in order to examine differences among populations and to reduce maternal effects in their offspring. Self-fertilized, greenhouse-collected seeds were then germinated and grown in either ‘warm’ (30/20Â°C, day/night) or ‘cool’ (10/5Â°C) growth chambers to specifically examine phenotypic plasticity.
The common garden experiment showed evidence for local adaptation for natives but not invasives, and revealed little difference among the two for traits that might confer invasive success (e.g. growth, seed production). In the growth chamber experiment, invasive populations exhibited more adaptive plasticity than natives for freezing tolerance (as measured by chlorophyll fluorescence). However there were no differences in the plastic responses to temperature among native and invasive populations for biomass or growth traits. Whereas photosynthetic responses to leaf temperature for all populations showed acclimatization dependent on growth temperature, there was no difference among native or invasive populations. Overall, there was evidence for higher plasticity in the invasive range for freezing tolerance – which may be advantageous in certain environments – but little evidence that invasive genotypes permit greater plasticity overall compared to native genotypes. These results suggest that the invasion of B. tectorum may be due more to ecosystem susceptibility and species-level traits as opposed to specific genotypes that confer success in the introduced range.
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1 - Wellesley College, Wellesley College Botanic Gardens, 106 Central Street, Wellesley, MA, 02481, USA
2 - University of California, Ecology & Evolutionary Biology Department, 1156 High Street, Santa Cruz, CA, 95064, USA
3 - University of California, Environmental Studies Department, 1156 High Street, Santa Cruz, CA, 95064, USA
Presentation Type: Oral Paper:Papers for BSA Sections
Location: Wasatch B/Cliff Lodge - Level C
Date: Monday, July 27th, 2009
Time: 8:45 AM