Interactive effects of O[sub 3] and CO[sub 2] enrichment on photosynthetic acclimation. I. Biochemical limitations

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

OSTI ID:7161994

Reid, C D; Fiscus, E L ^[1]

---

1. North Carolina State Univ., Raleigh, NC (United States)

To determine how Rubisco activity affects photosynthetic acclimation to combined elevated atmospheric CO[sub 2] and O[sub 3], soybeans (Glycine max) were grown in a 2 [times] 2 factorial design of atmospheric CO[sub 2] (current, +350[mu]l/l) and O[sub 3] (charcoal-filtered, 1.5[times] ambient) in open-top field chambers for one growing season. Soybeans were sampled for Rubisco activity at regular intervals throughout the seasons. A/C[sub i] measurements were carried out in the laboratory on field-grown soybean. Rubisco capacity to carboxylate CO[sub 2], determined by the slope of A/C[sub i] curve, was reduced most in CO[sub 2] [times] O[sub 3] treatment. Biochemical determinations of Rubisco activity and total content indicate that plants grown in CO[sub 2] [times] O[sub 3] show the lowest activity (45.5 vs 63.5 [mu]mol CO[sub 2].[sup [minus]2].s[sup [minus]1]) although ozone-treated plants initially had the lowest activity (33.1 [mu]mol.m[sup [minus]2].s[sup [minus]1] at 36 dap). In CO[sub 2][times]O[sub 3]-treated plants, the decline in carboxylation is due to a decline in Rubisco content and reduced activity whereas, in ozone-treated plants, only Rubisco content declined. Photosynthetic capacity at saturating C[sub i] was lowest under elevated CO[sub 2][times]O[sub 3], from 43 [mu]mol CO[sub 2].m[sup [minus]2].s[sup [minus]1] (control) to 19 [mu]mol CO[sub 2].m[sup [minus]2].s[sup [minus]1] (CO[sub 2][times]O[sub 3]). The combined effects of high CO[sub 2] and O[sub 3] on the biochemical limitation of photosynthesis are additive.

• OSTI ID: 7161994
• 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
CHEMICAL REACTIONS
ECOLOGICAL CONCENTRATION
FOOD
OXIDES
OXYGEN COMPOUNDS
OZONE
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
SOYBEANS
SYNTHESIS
VEGETABLES