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Linking Plant Physiology and Chemical Communication: Herbivore-Associated Volatiles Modulate Photosynthesis and Plant Resistance to Herbivores
No full textPlant volatile communication plays a major role in plant defense against insects, yet we know little about the mechanisms of volatile perception and plant physiological responses (i.e., changes in photosynthetic rates and stomatal conductance) to volatile compounds.
In Chapter 2, I investigate the role of stomata in volatile perception by plants. My findings indicate that maize (Zea mays) plants take up and perceive specific volatile compounds through open stomata, which prime anti-herbivore defense responses. Furthermore, environmental conditions that modify stomatal aperture and/or defense signaling affect the ability of maize plants to perceive herbivore-induced plant volatiles (HIPVs) and prime their defenses.
In Chapters 3 and 4, I characterize the physiological responses of three crop plant species to herbivore-associated volatile compounds and assess insect and plant performance. In chapter 3, I experimentally determined that upon perception of HIPVs, maize (Zea mays) and cotton (Gossypium hirustum) plants reduce photosynthetic rates and stomatal conductance. Upon subsequent herbivory, plant photosynthetic performance remained lower, which may have contributed to observed differences in plant and insect performance. Because little is known about how plants physiologically respond to insect-derived volatiles, in chapter 4, I characterized the photosynthetic and stomatal responses of squash (Cucurbita pepo) plants to the aggregation pheromone of a specialist herbivore, the striped cucumber beetle (Acalymma vittatum). I found that squash plants responded to A. vittatum aggregation pheromone by strongly reducing photosynthetic rates and stomatal conductance. I also found that exposure to A. vittatum aggregation pheromone does not deter insect feeding as plants exposed to the pheromone had more leaf area removed and less aboveground biomass at the end of the experiment.
Together, these results suggest that basic plant physiological processes are a critical component of plant volatile communication. These findings document the role of stomatal pores and photosynthetic responses to volatile perception with broad significance for anti-herbivore defense responses
