AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Healthy and Aphid-stressed Shrubby Plant (Baccharis salicifolia) Metabolomics Impact on Produced Biogenic Secondary Organic Aerosol
FATEMEH KHALAJ, Celia Faiola, Kailen Mooney, Swarup China, Christopher Anderton, Alber Rivas-Ubach, University of California, Irvine
Abstract Number: 557 Working Group: Aerosol Chemistry
Abstract Plants emit ~90% of hydrocarbons into the atmosphere globally, called biogenic volatile organic compounds (BVOCs). Climate change stressors enhance and modify plant metabolism with associated effects on BVOC emissions, and consequently, secondary organic aerosol production. However, the influence of plant stress on SOA production is not well understood. This project was the first to concurrently characterize changes in the plant metabolome and SOA production from healthy and aphid-stressed riparian shrubs Baccharis salicifolia—a common shrub found near rivers in California, an environment particularly susceptible to a changing climate and human influence—.
SOA was generated from Baccharis emissions using an Aerodyne, Inc. oxidation flow reactor (OFR). Particle composition and size distribution measurements were conducted with ACSM (Aerosol Chemical Speciation Monitor) and SMPS (Scanning Mobility Particle Sizer), respectively. BVOCs at the OFR inlet were characterized via thermo-desorption gas chromatography mass spectrometry (TD-GC-MS). On average, ten and five plants were used for healthy and stressed experiments, respectively, to generate SOA mass yield curves targeting particle concentrations ~1-13 μg m-3. Each healthy and stressed experiment was repeated four times with a different set of plants. At the end of each particle generation experiment, plant leaves from all plants in the enclosure were harvested separately, flash frozen in liquid nitrogen and analyzed off-line with liquid chromatography mass spectrometry at the Environmental Molecular Science Laboratory.
SOA mass yield curves were generated for the emission profile from both healthy and stressed plants, and SOA yields varied from 1-7% in both groups. Based on the leaf-level metabolome analysis via principal component analysis (PCA), there was a clear difference in the leaf-level metabolome between the aphid-stressed and control plants.