Sponsor
Portland State University. Department of Biology
First Advisor
Todd N. Rosenstiel
Term of Graduation
2011
Date of Publication
1-1-2011
Document Type
Thesis
Degree Name
Master of Science (M.S.) in Biology
Department
Biology
Language
English
Subjects
Root Carbon Fixation, Root Respiration, PEP Carboxylase, Poplar, Rhizodeposition, Roots (Botany) -- Research, Plants -- Effect of atmospheric carbon dioxide on, Carbon dioxide -- Metabolism, Plants -- Respiration
DOI
10.15760/etd.345
Physical Description
1 online resource (v, 82 pages)
Abstract
Roots live in and have evolved in a high carbon dioxide (CO₂) environment, yet relatively little research has been conducted on the impacts of soil dissolved inorganic carbon (DIC) on root metabolism. In this thesis, I explore the impacts of root-zone DIC on whole plant biomass accumulation, water use efficiency, and above-ground gas exchange. In addition, I explore the impacts of root-zone DIC on root processes: root PEP-Carboxylase activity, root respiration rate and root exudation of Krebs cycle organic acids.
Root-zone DIC did not impact biomass accumulation, leaf gas exchange parameters or water use efficiency under the growth conditions examined. Root-zone DIC did increase root PEP-Carboxylase activity, but decreased root respiration (both CO₂ production and O₂ consumption) and decreased organic acid exudation rates. Increase in measurement CO₂ partial pressure was found to cause an instantaneous decrease in root CO₂ production, and I provide evidence that changes in root metabolism (CO₂ uptake by roots) are part of the cause of this phenomenon. A hypothesized relationship between root respiration rate and Krebs cycle organic acid exudation was not supported by my data. I conclude that root-zone DIC has important impacts on critical functions of root metabolism, and should be considered as an important abiotic factor much in the same way atmospheric CO₂ is for leaves and whole plant biology.
Rights
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Persistent Identifier
http://archives.pdx.edu/ds/psu/7061
Recommended Citation
Matarese, Dawn Marie, "Impacts of Rhizosphere CO₂ on Root Phosphoenolpyruvate Carboxylase Activity, Root Respiration Rate and Rhizodeposition in Populus spp." (2011). Dissertations and Theses. Paper 345.
https://doi.org/10.15760/etd.345