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Abstract Detail

Ecological Section

Roche, Bernadette M. [1], Veatch-Blohm, Maren E. [1], Roberts, Roland P. [2].

Substrate and geographical population differentiation in the lyre-leaved rock cress, Arabidopsis lyrata.

Arabidopsis lyrata is a plant found in low competition environments that vary in edaphic conditions, including sandy loam, sand, serpentine rock, and other rocky substrates.  Individuals growing in different locations appear to have differences in rosette and flowering characteristics, which could be due to genetic differentiation among populations or alternatively, the result of phenotypic plasticity.  A common garden approach was employed to compare plant parameters related to germination, growth, leaf parameters, and flowering times for 8 populations of A. lyrata from NY, MD, and VA.  Seeds were collected in maternal half sib families from 3 serpentine (serpPS, serpRL, and serpSD), 2 rocky (rockyJW, rockyIM), and 3 sandy (sandPP, sandyJB, sandyGM) substrates, sown onto potting soil, and raised in 2 identical growth chambers for 12 weeks.  An RCBD was employed, where 1 individual from each of 8 maternal half-sib families from each of the 8 populations was planted into a complete block, replicated in 10 blocks for a total of 10 individuals per family per population.  Measurements of germination rate, growth rate, leaf parameters, and flowering times revealed significant differences (p<0.05) among populations, with the following trends.  Serpentine plants took longest to germinate, but were among the fastest to put on their 8th leaf; plants from rockyJW and sandyPP were the fastest to germinate, but were the slowest to put on their 8th leaf.  Plants from sandyPP had significantly higher leaf mass per area (LMA) than all other populations.  Leaf circularity was highest in rockyJW, next highest in rockyIM, sandyPP, and sandyGM, next highest in the three serpentine populations, and lowest in sandyJB.  Solidity (degree to which leaf edges were unruffled), was highest for rockyJW and lowest for sandyJB, but there was a great degree of overlap among most populations.  Of the 8 populations studied, 5 produced flowering stalks during the time allotted for the experiment.  A high percentage (>65%) of rockyJW and rockyIM plants produced flowering stalks, and 37% of serpPS plants produced flowering stalks.  The remainder of the populations either did not produce flowering stalks, or produced very few (<5%).  While we did see significant effects of population on many plant traits, there were very few consistent trends either by substrate type (serpentine, sandy, rocky,) or geographical region (NY, MD, VA).  This data set will be linked with a study of genetic differences based on microsatellites in the same populations, and perhaps further trends will become evident.

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1 - Loyola University Maryland, Biology, 4501 N. Charles Street, Baltimore, MD, 21210, USA

population differentiation
Arabidopsis lyrata.

Presentation Type: Poster:Posters for Sections
Session: P
Location: Eyrie/Boise Centre
Date: Monday, July 28th, 2014
Time: 5:30 PM
Number: PEC016
Abstract ID:707
Candidate for Awards:None

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