<p> Terrestrial and oceanic biomass carbon sinks help reduce anthropogenic CO<sub>2</sub> emissions and mitigate the long-term effect of increasing atmospheric CO<sub>2</sub>. Woody plants have large carbon pools because of their long residence time, however N availability can negatively impact tree responses to elevated CO<sub>2</sub>. Seasonal cycling of internal N in trees is a component that contributes to fitness especially in N limited environments. It involves resorption from senescing leaves of deciduous trees and storage as vegetative storage proteins (VSP) in perennial organs. <i>Populus </i> is a model organism for tree biology that efficiently recycles N. Bark storage proteins (BSP) are the most abundant VSP that serves as seasonal N reserves. Here I show how poplar growth is influenced by N availability and how growth is influenced by shoot competition for stored N reserves. I also provide data that indicates that auxin mediates BSP catabolism during renewed shoot growth. Understanding the components of N accumulation, remobilization and utilization can provide insights leading to increasing N use efficiency (NUE) of perennial plants.</p>
| Identifer | oai:union.ndltd.org:PROQUEST/oai:pqdtoai.proquest.com:10130093 |
| Date | 30 June 2016 |
| Creators | Egekwu, Chioma |
| Publisher | University of Maryland, College Park |
| Source Sets | ProQuest.com |
| Language | English |
| Detected Language | English |
| Type | thesis |
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