The photosynthetic acclimation of Lolium perenne in response to three years growth in a free-air CO2 enrichment (FACE) system
- Univ. of Essex (United Kingdom); Univ. of Writtle College (United Kingdom)
Pure stands of Ryegrass were in their third year of growth in the field, exposed to either ambient (355 μmol mol-1), or elevated (600 μmol mol-1) atmospheric CO2 concentration. A Free-Air CO2 Enrichment (FACE) system was used to maintain the elevated CO2 concentration whilst limiting experimental constraints on the field conditions. The theoretically predicted increase in the net rates of CO2 uptake per unit leaf area (A {mu}mol mol-1) as a consequence, primarily, of the suppression of photorespiration by CO2 a competitive inhibitor of RubP oxygenation by Rubisco, was observed for the Lolium perenne studied. Also observed was a general decline in leaf evapotranspiration (E) consistent with observations of increased water use efficiency of crops grown in elevated CO2. Enhancement of leaf A in the FACE grown L. perenne ranged from 26.5 1 % to 44.95% over the course of a diurnal set of measurements. Whilst reductions in leaf E reached a maximum of 16.61% over the same diurnal course of-measurements. The increase in A was reconciled with an absence of the commonly observed decline in Vcmax as a measure of the maximum in vivo carboxylation capacity of the primary carboxylasing enzyme Rubisco and Jmax a measure of the maximum rate of electron transport. The manipulation of the source sink balance of the crop, stage of canopy regrowth or height in the canopy had no effect on the observation of a lack of response. The findings of this study will be interpreted with respect to the long term implications of C3 crops being able to adapt physiologically to maximize the potential benefits conferred by growth in elevated CO2.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 374435
- Report Number(s):
- BNL-63365; ON: DE96014907; TRN: 96:005285
- Resource Relation:
- Other Information: TH: Thesis (Ph.D); PBD: Aug 1996
- Country of Publication:
- United States
- Language:
- English
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