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Titolo:
Elevated CO2 enhances water relations and productivity and affects gas exchange in C-3 and C-4 grasses of the Colorado shortgrass steppe.
Autore:
Morgan, JA; LeCain, DR; Mosier, AR; Milchunas, DG;
Indirizzi:
USDA ARS, Crops Res Lab, Rangeland Resources Res Unit, Ft Collins, CO 80526 USA USDA ARS Ft Collins CO USA 80526 urces Res Unit, Ft Collins, CO 80526 USA USDA ARS, Soil Plant Nutr Res Unit, Ft Collins, CO 80522 USA USDA ARS Ft Collins CO USA 80522 Nutr Res Unit, Ft Collins, CO 80522 USA Colorado State Univ, Dept Rangeland Ecosyst Sci, Ft Collins, CO 80523 USA Colorado State Univ Ft Collins CO USA 80523 Sci, Ft Collins, CO 80523 USA Colorado State Univ, Nat Resources Ecol Lab, Ft Collins, CO 80523 USA Colorado State Univ Ft Collins CO USA 80523 Lab, Ft Collins, CO 80523 USA
Titolo Testata:
GLOBAL CHANGE BIOLOGY
fascicolo: 4, volume: 7, anno: 2001,
pagine: 451 - 466
SICI:
1354-1013(200104)7:4<451:ECEWRA>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
TALLGRASS PRAIRIE ECOSYSTEM; PASCOPYRUM-SMITHII C-3; CARBON-DIOXIDE CONCENTRATIONS; BOUTELOUA-GRACILIS C-4; ATMOSPHERIC CO2; GROWTH-RESPONSE; BIOMASS PRODUCTION; ENRICHMENT; NITROGEN; PLANTS;
Keywords:
Bouteloua gracilis; Pascopyrum smithii; global change; photosynthesis; acclimation; grazing; defoliation;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Morgan, JA USDA ARS, Crops Res Lab, Rangeland Resources Res Unit, 1701 CtrAve, Ft Collins, CO 80526 USA USDA ARS 1701 Ctr Ave Ft Collins CO USA 80526 ins, CO 80526 USA
Citazione:
J.A. Morgan et al., "Elevated CO2 enhances water relations and productivity and affects gas exchange in C-3 and C-4 grasses of the Colorado shortgrass steppe.", GL CHANGE B, 7(4), 2001, pp. 451-466

Abstract

Six open-top chambers were installed on the shortgrass steppe in north-eastern Colorado, USA from late March until mid-October in 1997 and 1998 to evaluate how this grassland will be affected by rising atmospheric CO2. Threechambers were maintained at current CO2 concentration (ambient treatment),three at twice ambient CO2, or approximately 720 mu mol mol(-1) (elevated treatment), and three nonchambered plots served as controls. Above-ground phytomass was measured in summer and autumn during each growing season, soilwater was monitored weekly, and leaf photosynthesis, conductance and waterpotential were measured periodically on important C-3 and C-4 grasses. Mid-season and seasonal above-ground productivity were enhanced from 26 to 47%at elevated CO2, with no differences in the relative responses of C-3/C-4 grasses or forbs. Annual above-ground phytomass accrual was greater on plots which were defoliated once in mid-summer compared to plots which were notdefoliated during the growing season, but there was no interactive effect of defoliation and CO2 on growth. Leaf photosynthesis was often greater in Pascopyrum smithii (C-3) and Bouteloua gracilis (C-4) plants in the elevated chambers, due in large part to higher soil water contents and leaf water potentials. Persistent downward photosynthetic acclimation in P. smithii leaves prevented large photosynthetic enhancement for elevated CO2-grown plants. Shoot N concentrations tended to be lower in grasses under elevated CO2, but only Stipa comata (C-3) plants exhibited significant reductions in N under elevated compared to ambient CO2 chambers. Despite chamber warming of2.6 degreesC and apparent drier chamber conditions compared to unchamberedcontrols, above-ground production in all chambers was always greater than in unchambered plots. Collectively, these results suggest increased productivity of the shortgrass steppe in future warmer, CO2 enriched environments.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 10/07/20 alle ore 09:13:42