DOI: 10.5061/dryad.547d7wmb3
title: The floral volatiles of Aquilegia coerulea for three populations grown at two water and temperature regimes, together with day and evening emission

description: Premise of the study: Shifts in abiotic factors can affect many plant
 traits, including floral volatiles. This study examines the response of
 floral volatiles to water availability, and whether phenotypic plasticity
 to water differs among populations. Furthermore, it investigates genetic
 differentiation in floral volatiles, determines the effect of temperature
 on phenotypic plasticity to water, and assesses temporal variation in
 floral scent emission between day and evening, since pollinator visitation
 differs at those times. Methods: Rocky Mountain columbine plants
 (Aquilegia coerulea), started from seeds collected in three wild
 populations in Colorado, Utah, and Arizona, were grown under two water
 treatments in a greenhouse in Madison, Wisconsin, USA. One population was
 also grown under the two water treatments, at two temperatures. Air
 samples were collected from enclosed flowers using dynamic headspace
 methods and floral volatiles were identified and quantified by gas
 chromatography (GC) with mass spectrometry (MS) detection. Key Results:
 Emission of three floral volatiles increased in the wetter environment,
 indicating phenotypic plasticity. The response of six floral volatiles to
 water differed among populations, suggesting genetic differentiation in
 phenotypic plasticity. Five floral volatiles varied among populations, and
 emission of most floral volatiles was greater during the day. Conclusions:
 Phenotypic plasticity to water permits a quick response of floral
 volatiles in changing environments. The genetic differentiation in
 phenotypic plasticity suggests that phenotypic plasticity can evolve but
 complicates predictions of the effects of environmental changes on a plant
 and its pollinators.
description: Plants from the three populations were grown from seeds in one
 room, kept at 20° C during the day and 7.7° C at night, at the Walnut
 Street greenhouses in Madison, Wisconsin (the cool room). Plants for the
 CO population were also grown in a warm room kept at 25.5° C during the
 day, and 13.3° C at night, which represented a difference from the cool
 room of 5.5° C during the day, and 5.6° C at night. The temperature regime
 was linked to the light regime in the greenhouse rooms. Within each room,
 plants within populations were randomly assigned to an every fifth (wet)
 or every eighth day (dry) water treatment. The same volume of water was
 added to each plant on a given day, and only the frequency of watering
 changed between the two water treatments. These two water treatments
 represented unstressed and stressed conditions. Plants were grown for
 about four months in their respective treatments, and when most plants had
 ten leaves, they were vernalized for 2 months at 4º C to trigger flowering
 before being returned to their respective greenhouse room. While flowering
 time varied with temperature and water treatment (Brunet and Larson-
 Rabin, 2012), most plants started flowering 2.5-3 months after being
 returned to their respective treatments. To measure the
 volatiles emitted from columbine flowers, we collected air samples from
 enclosed flowers using dynamic headspace methods and identified and
 quantified compounds by gas chromatography (GC) with mass spectrometry
 (MS) detection. Volatiles were collected from a single receptive female
 flower per plant, and from up to seven plants per day for most days
 between March 22 and April 10. We used a chiral GC column in order to
 separate and measure optical enantiomers of some of the floral
 volatiles. We examined the impact of population and
 water at low temperature; the impact of water at two temperatures for the
 Colorado population, and examined the temporal variation in floral
 volatile emission between day and evening (including dusk) because
 hawkmoths tend to visit these plants at dusk.
description: Variables are explained in the Read me file