Publikationsdatum:
2011-06-09
Beschreibung:
During the first few years of elevated atmospheric [CO 2 ] treatment at the Nevada Desert FACE Facility, photosynthetic downregulation was observed in desert shrubs grown under elevated [CO 2 ], especially under relatively wet environmental conditions. Nonetheless, those plants maintained increased A sat (photosynthetic performance at saturating light and treatment [CO 2 ]) under wet conditions, but to a much lesser extent under dry conditions. To determine if plants continued to downregulate during long-term exposure to elevated [CO 2 ], responses of photosynthesis to elevated [CO 2 ] were examined in two dominant Mojave Desert shrubs, the evergreen Larrea tridentata and the drought-deciduous Ambrosia dumosa , during the eighth full growing season of elevated [CO 2 ] treatment at the NDFF. A comprehensive suite of physiological processes were collected. Furthermore, we used C labeling of air to assess carbon allocation and partitioning as measures of C sink activity. Results show that elevated [CO 2 ] enhanced photosynthetic performance and plant water status in Larrea , especially during periods of environmental stress, but not in Ambrosia . δ 13 C analyses indicate that Larrea under elevated [CO 2 ] allocated a greater proportion of newly assimilated C to C sinks than Ambrosia . Maintenance by Larrea of C sinks during the dry season partially explained the reduced [CO 2 ] effect on leaf carbohydrate content during summer, which in turn lessened carbohydrate build-up and feedback inhibition of photosynthesis. δ 13 C results also showed that in a year when plant growth reached the highest rates in 5 years, 4% ( Larrea ) and 7% ( Ambrosia ) of C in newly emerging organs were remobilized from C that was assimilated and stored for at least 2 years prior to the current study. Thus, after 8 years of continuous exposure to elevated [CO 2 ], both desert perennials maintained their photosynthetic capacities under elevated [CO 2 ]. We conclude that C storage, remobilization, and partitioning influence the responsiveness of these desert shrubs during long-term exposure to elevated [CO 2 ]. Content Type Journal Article Pages 1-16 DOI 10.1007/s00442-011-1996-y Authors Iker Aranjuelo, Fisiologia Vegetal y Agrobiologia, Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC-Gobierno de Navarra, Campus de Arrosadia, 31192 Mutilva Baja, Spain Allison L. Ebbets, School of Life Sciences, University of Nevada, Las Vegas, NV 89154-4004, USA R. Dave Evans, School of Biological Sciences, Washington State University, Pullman Washington, 99164 USA David T. Tissue, Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA Salvador Nogués, Unitat de Fisologia Vegetal, Facultat de Biologia, Universitat de Barcelona, Diagonal 645, 08028 Barcelona, Spain Natasja van Gestel, Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA Paxton Payton, Department of Biological Sciences, Texas Tech University, Lubbock, TX 79409-3131, USA Volker Ebbert, Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA Williams W. Adams III, Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO 80309-0334, USA Robert S. Nowak, Department of Natural Resources and Environmental Science, University of Nevada, Reno Nevada, 89557 USA Stanley D. Smith, School of Life Sciences, University of Nevada, Las Vegas, NV 89154-4004, USA Journal Oecologia Online ISSN 1432-1939 Print ISSN 0029-8549
Print ISSN:
0029-8549
Digitale ISSN:
1432-1939
Thema:
Biologie
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