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dc.contributor.authorGreen, Laura Elizabeth
dc.date.accessioned2009-11-18T21:22:59Z
dc.date.available2009-11-18T21:22:59Z
dc.date.issued2009-11-18T21:22:59Z
dc.date.submittedJuly 2009
dc.identifier.urihttp://hdl.handle.net/1928/9959
dc.description.abstractControl of stomatal aperture is the primary way plants regulate gas exchange in the short-term, but what triggers stomatal responses to water stress is still debated. Chlorophyll-a fluorescence imaging, local leaf temperature, and gas exchange were measured simultaneously following a cut to primary leaf vein of Helianthus annuus to access the effect of local leaf xylem cavitation on leaf function. The treatment was repeated under 3 different vapor pressure deficit (VPD) conditions. Surprisingly, photosynthesis (A) and stomatal conductance (gs) responded inversely immediately following the treatment, indicating that A was not CO2 limited by stomatal closure. Comparisons of fluorescence images and temperature data showed that while both A and gs responded heterogeneously across the measured leaf area, local responses did not correspond spatially or temporally, suggesting that each was the result of a different mechanism and/or was initiated by a separate signal. Since the stomatal response varied with VPD but A did not, it is likely that only gs was ultimately responding to a hydraulic signal. Both A and gs recovered to near steady state levels by 900s after the cut. These results indicate that stomata respond immediately to a sudden hydraulic perturbation and that hydraulic redundancy in sunflower is sufficient to allow quick recovery to local interruption of vascular system. This experiment also provides evidence of transient de-coupling of A and gs following wounding.en_US
dc.language.isoen_USen_US
dc.subjectstomataen_US
dc.subjectelectrical potentialen_US
dc.subjectheterogeneous behavioren_US
dc.subjectphotosynthesisen_US
dc.subjecthydraulic conductanceen_US
dc.subjecthydraulic architectureen_US
dc.subject.lcshPhotosynthesis
dc.subject.lcshTranspiration.
dc.subject.lcshStomata
dc.subject.lcshCommon sunflower--Physiology
dc.titleTransient de-coupling of photosynthesis and stomatal conductance in response to leaf primary vein cut in Helianthus annuusen_US
dc.typeThesisen_US
dc.description.degreeScienceen_US
dc.description.levelMastersen_US
dc.description.departmentUniversity of New Mexico. Biology Dept.en_US
dc.description.advisorPockman, William
dc.description.committee-memberHanson, David
dc.description.committee-memberSinsabaugh, Robert
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