Grant: Research Tools and Instruments - Category 1 (<$150,000)

Chlorophyll a fluorescence combined with CO2 gas exchange is now a technique of choice to assess photosynthetic performance and the effects of environmental stress in plants and algae. The Li-Cor 6400XRT represents state-of-the-art instrumentation for this purpose and will support three independent research programmes in the general area of plant stress and development. First, the ability to combine measurements of in vivo CO2 gas exchange with concomitant measurements of chlorophyll fluorescence is crucial to elucidating the mechanism underlying the regulation of stress-induced leaf variegation in the model plant, Arabidopsis thaliana. In addition, in vivo CO2 gas exchange and chlorophyll fluorescence measurements coupled with gene expression measurements are critical to understanding the mechanism underlying the acclimation of specific cereal cultivars to elevated CO2 and warm temperatures typically associated with global warming and climate change. Second, Dr. Macfie's research programme is focussed on the elucidation of the mechanisms by which plants respond to potentially toxic metal ions. This includes identification of the biochemical and molecular mechanism(s) in operation, the corresponding signalling pathways and the genes or gene families involved. Metal stress induced changes in biomass accumulation should be reflected in reductions in photosynthetic capacity and photosynthetic efficiency. In turn, this should be reflected in alterations in CO2 assimilation rates, PSII photochemical efficiency and energy partitioning as measured by in vivo chlorophyll a fluorescence and CO2 gas exchange. Third, Dr. Henry's current research focuses on plant and natural ecosystem responses to the combined effects of climate warming and atmospheric nitrogen deposition, two ecologically important global change factors that are projected to increase over the next century. CO2 assimilation combined with chlorophyll a fluorescence data will help in the prediction of the future productivity and functionality of temperate ecosystems in response to global environmental change, and will contribute to the mechanistic framework underlying feedbacks between the atmosphere and biotic systems in climate change models.