CO[sub 2] alters water use, carbon gain, and yield in a natural grassland

Conference · Wed Jun 01 04:00:00 EDT 1994 · Bulletin of the Ecological Society of America; (United States)

OSTI ID:7162312

Sala, O E; Jackson, R B; Field, C B; Mooney, H A ^[1]

---

1. Stanford Univ., CA (United States)

Global atmospheric CO[sub 2] is increasing at a rate of 1.5 to 2 ppm per year and is predicted to double by the end of the next century. Understanding how terrestrial ecosystems will respond in this changing environment is an important goal of current research. Here we present results from a field study of elevated CO[sub 2] in a California annual grassland. Elevated CO[sub 2] led to lower leaf-level stomatal conductance and transpiration (approximately 50%) and higher mid-day leaf water potentials (30 to 35%) in the most abundant species of the grassland, Avena barbata Brot. Higher CO[sub 2] concentrations also resulted in greater mid-day photosynthetic rates (70% on average). The effects of CO[sub 2] on stomatal conductance and leaf water potential decreased towards the end of the growing season, when Avena began to show signs of senescence. Water-use efficiency was doubled in elevated CO[sub 2], as estimated by instantaneous gas-exchange measurements and seasonal carbon isotope discrimination. Increases in CO[sub 2] and photosynthesis resulted in more seeds per plant (30%) and taller and heavier plants (27% and 41%, respectively).

• OSTI ID: 7162312
• Report Number(s): CONF-940894--
• Conference Information: Journal Name: Bulletin of the Ecological Society of America; (United States) Journal Volume: 75:2
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BIOLOGICAL EFFECTS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
ECOLOGICAL CONCENTRATION
ECOSYSTEMS
FIELD TESTS
GRAMINEAE
GROWTH
LILIOPSIDA
MAGNOLIOPHYTA
OXIDES
OXYGEN COMPOUNDS
PLANT GROWTH
PLANTS
RANGELANDS
REPRODUCTION
TERRESTRIAL ECOSYSTEMS
TESTING