Faiola Celia L, Pullinen Iida, Buchholz Angela, Khalaj Farzaneh, Ylisirniö Arttu, Kari Eetu, Miettinen Pasi, Holopainen Jarmo K, Kivimäenpää Minna, Schobesberger Siegfried, Yli-Juuti Taina, Virtanen Annele
Department of Ecology and Evolutionary Biology and Department of Chemistry, University of California Irvine, Irvine, California 92697, United States.
Department of Applied Physics, University of Eastern Finland, P.O. Box 1626, 70211 Kuopio, Finland.
ACS Earth Space Chem. 2019 Sep 19;3(9):1756-1772. doi: 10.1021/acsearthspacechem.9b00118. Epub 2019 Aug 14.
One barrier to predicting biogenic secondary organic aerosol (SOA) formation in a changing climate can be attributed to the complex nature of plant volatile emissions. Plant volatile emissions are dynamic over space and time, and change in response to environmental stressors. This study investigated SOA production from emissions of healthy and aphid-stressed Scots pine saplings via dark ozonolysis and photooxidation chemistry. Laboratory experiments using a batch reaction chamber were used to investigate SOA production from different plant volatile mixtures. The volatile mixture from healthy plants included monoterpenes, aromatics, and a small amount of sesquiterpenes. The biggest change in the volatile mixture for aphid-stressed plants was a large increase (from 1.4 to 7.9 ppb) in sesquiterpenes-particularly acyclic sesquiterpenes, such as the farnesene isomers. Acyclic sesquiterpenes had different effects on SOA production depending on the chemical mechanism. Farnesenes suppressed SOA formation from ozonolysis with a 9.7-14.6% SOA mass yield from healthy plant emissions and a 6.9-10.4% SOA mass yield from aphid-stressed plant emissions. Ozonolysis of volatile mixtures containing more farnesenes promoted fragmentation reactions, which produced higher volatility oxidation products. In contrast, plant volatile mixtures containing more farnesenes did not appreciably change SOA production from photooxidation. SOA mass yields ranged from 10.8 to 23.2% from healthy plant emissions and 17.8-26.8% for aphid-stressed plant emissions. This study highlights the potential importance of acyclic terpene chemistry in a future climate regime with an increased presence of plant stress volatiles.
预测在不断变化的气候中生物源二次有机气溶胶（SOA）形成的一个障碍可归因于植物挥发性排放物的复杂性质。植物挥发性排放物在空间和时间上是动态的，并会因环境压力源而变化。本研究通过暗臭氧分解和光氧化化学研究了健康和受蚜虫胁迫的苏格兰松树苗排放物产生的SOA。使用间歇反应室的实验室实验用于研究不同植物挥发性混合物产生的SOA。健康植物的挥发性混合物包括单萜、芳烃和少量倍半萜。受蚜虫胁迫植物的挥发性混合物最大的变化是倍半萜（特别是无环倍半萜，如法呢烯异构体）大幅增加（从1.4 ppb增至7.9 ppb）。无环倍半萜对SOA产生的影响因化学机制而异。法呢烯抑制臭氧分解产生的SOA形成，健康植物排放物的SOA质量产率为9.7 - 14.6%，受蚜虫胁迫植物排放物的SOA质量产率为6.9 - 10.4%。含有更多法呢烯的挥发性混合物的臭氧分解促进了碎片化反应，产生了挥发性更高的氧化产物。相比之下，含有更多法呢烯的植物挥发性混合物并没有明显改变光氧化产生的SOA。健康植物排放物的SOA质量产率在10.8%至23.2%之间，受蚜虫胁迫植物排放物的SOA质量产率在17.8 - 26.8%之间。这项研究强调了在未来植物应激挥发物增加的气候条件下，无环萜烯化学的潜在重要性。
