Title
Impact of Environmental Factors on Floral Scent Emission of Gelsemium sempervirens
Subject
floral scent, floral scent emission, SPME arrow, environmental factors, Gelsemium sempervirens, Carolina Jessamine, volatile organic compounds, VOCs, GC-MS
Description
The goal of this project was to study the effects of environmental factors (temperature, humidity, barometric pressure, light intensity, and time of day) on the floral scent emissions of Gelsemium sempervirens. Floral scent emission affects pollinator attraction and can have agricultural implications. Previous research at USCL identified the volatile organic compounds (VOCs) emitted from L and S floral morphs in wild and cultivated populations of this plant. That study did not evaluate environmental factors but identified them as a source of variation in the data. For this project I used a new sampling method, the SPME (solid phase microextraction) arrow, which enabled me to monitor floral scent in situ and directly study the impacts of these factors. I hypothesized that total VOCs would increase with later time of day, higher temperatures, lower humidity, and lower barometric pressure. I collected floral scent samples from L morph flowers using the SPME arrow and measured environmental factors using a LabQuest system with temperature, pressure, humidity, and light intensity probes. I analyzed the floral scent compounds using gas chromatography-mass spectroscopy (GC-MS) to determine correlations between environmental factors and floral scent emission. Initial data analysis involved compiling all data into Microsoft excel and transporting it to a statistical analysis package for non-metric multidimensional scaling (NMDS) analyses. The floral scent profiles comprised 174 compounds from all 21 samples (average 53 compounds per sample), with 4 compounds common to all sample which included benzaldehyde, benzyl alcohol, alpha-farnesene, and alpha-ionone. 3 additional compounds were common to at least 19 of the samples and they included 4-anisaldehyde, benzyl benzoate, and acetophenone. I found that the total scent emission (measured by total GC-MS peak area) appeared to correlate with time of day, temperature, and relative humidity. I observed that VOC quantity increased later in the day, which was consistent with my hypothesis. In addition, I determined that relative amounts of specific VOCs changed throughout the day and floral scent emissions changed with varying environmental conditions. Floral scent profile was strongly correlated to the flower sampled (Pseudo-F=3.5, df=5, P<<0.001; Fig. 2) and not to the time of day (P=0.8) nor temperature (P=0.8). Environmental factors such as relative humidity (P=0.12), rain on the day of a sampling (P=0.16), and barometric pressure (P=0.30) may affect floral scent profile, but further analysis is needed to verify this. This study will lend relevance to understanding the effects of environmental factors on floral scent emission, not only for this flower but also for many similar species. Connections between environmental factors and floral scent will contribute to a better understanding of pollinator visitation patterns and how they are affected by the surrounding environment.
Creator
Charis Grabbe
Date
April 2023
Rights
Attribution-NonCommercial-NoDerivs (CC BY-NC-ND)
Format
pdf
Title
Impact of Environmental Factors on Floral Scent Emission of Gelsemium sempervirens
Date (Month, Year)
April 2023
Conference Name
Discover UofSC
Location (City, State; City, Country)
Columbia, SC