Donahue, Leanne , Griffin-Nolan, Robert , Hamilton, Jason , Melcher, Peter .
A rapid fluorescence imaging screening protocol to assess PSII electron efficiency of plants.
Plants have both direct and indirect defense traits in response to changes in both abiotic (mechanical,UV, water and/or temperature stress) and biotic (herbivore attack, plant-plant interactions) stressors. For example, plants can elicit direct defenses to reduce the susceptibility of attacking insects and in response to changes in abiotic conditions that result in increased plant fitness. Plants also have indirect defenses, such as the production of volatile organic compounds that can facilitate top-down control of herbivore populations by increasing the foraging success of herbivore predators and parasitoids. Abiotic and biotic induced plant responses are not restricted to secondary metabolism, but also include changes in various primary metabolic pathways. For example, depending on the herbivore feeding style, a broad range of effects of herbivory on photosynthesis as the plant's main primary metabolic process has been reported. Pioneering studies of herbivore-induced changes in photosynthesis found the majority of defoliating herbivores causing an increase in photosynthetic activity, whereas mesophyll and phloem feeders, stem borers and gall formers mainly decreased photosynthesis in the remaining plant tissue. Recent gas exchange measurements and PSII electron efficiency studies from the use Fluorimaging systems have demonstrated reduced photosynthesis in herbivore- or mechanically damaged plant tissue demonstrating negative impacts of herbivory on plant fitness. Because these leaf-level photosynthetic measurements are time consuming, we developed a rapid screening method that allows one to measure variation in PSII electron efficiency in response to chemical treatments on many (up to 96) plants simultaneously using a CF Fluorescence Imaging system (Technologia, UK). We developed this method so that it can be used in both studies investigating how abiotic and biotic stress impacts leaf level fitness. Our main focus in this study was to address insect herbivory on leaf-level fitness by specifically monitoring changes in PSII electron efficiency as well as leaf level photosynthesis using a LICOR gas exchange system. We tested various photosynthetic inhibitors on leaves of Brassica rapa (Fast Plant) and Nicotiana attenuata (Tobacco), in conjunction with applying mechanical damage to leaves with the goal to determine how variations in herbivore saliva applied to leaf surfaces or injected into leaves alter leaf level fitness.
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1 - Ithaca College, Biology Department, 953 Danby Road, Ithaca, NY, 14850, USA
2 - Ithaca College, Environmental Sciences and Studies, 953 Danby Road, Ithaca, NY, 14850, United States
photosynthetic efficiency (PRI)
Presentation Type: Poster:Posters for Sections
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM