Associate Professor Michigan State University, United States
Volatile organic compounds (VOCs) are secondary metabolites emitted by all plant species in unique, species-specific blends. A species’ VOC mixture is not static, however, and is known to change in response to stressful events. These induced VOCs, which relay information on imminent stressors to nearby plants and organisms, are crucial forms of communication for plant communities and aid in plant defense. Currently, there is a lack of knowledge on how abiotic climate change stressors affect chemical emissions for many plant species in natural plant communities. To address this knowledge gap, we collected VOC emissions from Canada goldenrod (Solidago canadensis) within five climate treatments of the Rainfall Exclusion eXperiment (REX) at the Kellogg Biological Station Long Term Ecological Research (KBS LTER) site (Hickory Corners, MI, USA): warming, drought, warming + drought, irrigation, and no treatment (ambient). These treatments were applied to the plants in situ using open-top chambers to mimic climate warming and rainout shelters to manipulate water availability for the plants.
Overall, we found both warming and drought changed VOC composition and abundance for Solidago canadensis, but warming had a greater effect than drought overall. While there was no effect of any climate treatment on VOC emissions prior to the start of drought treatments, after three weeks of drought and five months of warming, the composition of plant VOCs differed between the warming and ambient treatments, and warming treatments also decreased overall abundances of VOCs. There was little effect of drought on overall VOC composition and abundance. Certain VOCs, such as caryophyllene and ethanone, 1-(4-ethylphenyl)-, experienced especially strong reductions in their abundances under warming and/or drought. As plant VOCs play an important role in plant defense, community dynamics, and plant-insect interactions, experiments that investigate these stress-induced shifts in plant emissions are crucial in our efforts to predict and plan for climate change effects on plant communities.