Plant nitrogen budget under elevated carbon dioxide level: Regulation by nitrogen absorption and assimilation. Progress report, October 1, 1995--July 31, 1996
The overall objective is to assess root physiological and morphological characteristics that may alter plant N acquisition capacity in response to rising atmospheric CO{sub 2} concentration. There is increasing evidence that plant and ecosystem responses to elevated levels of CO{sub 2} will ultimately depend on availability and acquisition rate of other resources such as N. Therefore, knowledge of any changes in root capacity to acquire N is crucial in predicting plant and ecosystem responses to high CO{sub 2}. Here the authors are testing two major hypotheses: (1) elevated CO{sub 2} will enhance root N uptake kinetics and (2) CO{sub 2} enrichment will increase root preference for NO{sub 3}{sup {minus}} as opposed to NH{sub 4}{sup +}. High CO{sub 2} enhances root energy status which should in turn favor energy-intensive processes such as NO{sub 3}{sup {minus}} uptake and assimilation. The above hypotheses are being tested on a range of species from native and agricultural ecosystems using a combination of field, lab and growth chamber studies. The authors have demonstrated a considerable interspecies variation in root N uptake responses to CO{sub 2} enrichment and attempts are now underway to evaluate if such variations are correlated with different functional groups. A comprehensive growth model, using physiological and allocation parameters, has been largely completed and will be used to analyze the completed experimental data.
- Research Organization:
- New Mexico State Univ., Las Cruces, NM (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- FG03-95ER62126
- OSTI ID:
- 656508
- Report Number(s):
- DOE/ER/62126-T1-Pt.2; ON: DE98007388; TRN: AHC29817%%63
- Resource Relation:
- Other Information: PBD: [1998]
- Country of Publication:
- United States
- Language:
- English
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