Thesis
Leaf isotope exchange and isotopic equilibrium in Flaveria bidentis and Nicotiana tabacum
Washington State University
Master of Science (MS), Washington State University
12/2015
Handle:
https://hdl.handle.net/2376/103062
Abstract
The oxygen isotope composition of CO2 is an important tool for terrestrial carbon-sink portioning and is controlled by the isotopic equilibration of CO2 and H2O via the enzyme carbonic anhydrase. (CA). The extent of this equilibration ([Theta]) will determine the relative influence of leaf H2O isotopes on CO2. In turn, [Theta] is determined by the estimation of H2O isotopes at the site of exchange, the rate of activity of CA, and the flux of CO2 through the leaf. Differences in [Theta] between C3 and C4 plants have been attributed to differences in CA location, causing an overestimation of the composition of water at the site of exchange (dex). The C3 plant Nicotiana tabacum and the C4 plant Flaveria bidentis have been used to test whether manipulating either estimates of dex or the flux of CO2 through the leaf will influence [Theta]. Both species contain high CA activity and both have [Theta] values less than predicted based on CA. Measurements of [Theta] were insensitive to changes in the estimation of dex for both species and were highly sensitive to changes in stomatal conductance. The data presented here indicate that 1) CA assays based on bulk-leaf CA overestimate CA activity at the site of exchange 2) dex is not being overestimated in either species 3) flux of CO2 through the leaf is the main driver of [Theta].
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Details
- Title
- Leaf isotope exchange and isotopic equilibrium in Flaveria bidentis and Nicotiana tabacum
- Creators
- Jeffrey Emanuel Ritter
- Contributors
- Asaph B. Cousins (Chair)Eric Roalson (Committee Member) - Washington State University, School of Biological SciencesGerald E Edwards (Committee Member) - Washington State University, School of Biological Sciences
- Awarding Institution
- Washington State University
- Academic Unit
- School of Biological Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 47
- Identifiers
- 99900525027401842
- Language
- English
- Resource Type
- Thesis