Photosynthetic response of Bragg soybean leaves adapted to different CO/sub 2/ environments

Journal Article · · Crop Sci.; (United States)

OSTI ID:5768141

Valle, R; Mishoe, J W; Campbell, W J; Jones, J W; Allen, Jr, L H

Carbon dioxide exchange rate (CER) were measured during seed fill on leaflets of soybean (Glycine max (L.) Merr. Bragg) plants grown at 330 and 660 ..mu..mol mol/sup -1/ CO/sub 2/ environments in outdoor growth chambers to investigate their photosynthetic response to light. During midday periods at the R5 growth stage, the plants were submitted to short-term CO/sub 2/ levels ranging from 90 to 990 ..mu..mol mol/sup -1/ to determine differences in leaf photosynthetic response caused by CO/sub 2/ acclimation. The data were fitted to a rectangular hyperbola of the Michaelis-Menten form in which the independent variable was radiation or CO/sub 2/. Light and CO/sub 2/ compensation points were calculated from the parameters of the model. Light response curves showed that leaflets grown and measured at 660 ..mu..mol mol/sup -1/ CO/sub 2/ had higher CER asymptotes, higher apparent Michaelis-Menten constants for light, higher apparent quantum yield, and lower light compensation points than leaflets adapted to and measured at 330 ..mu..mol mol/sup -1/ CO/sub 2/. The CER-CO/sub 2/ curve parameters also indicated higher asymptotic ceilings of CER at high CO/sub 2/ for the higher CO/sub 2/ adapted leaflets. The CO/sub 2/ compensation point was significantly lower in leaflets adapted to high CO/sub 2/ levels than those adapted to ambient CO/sub 2/, indicating a decrease in photorespiration. It was concluded that during seed fill, leaflets adapted to high CO/sub 2/ environments exhibited a capability to utilize CO/sub 2/ and radiation more efficiently at elevated CO/sub 2/ and throughout all light levels than leaflets grown at low CO/sub 2/.

• Research Organization: Univ. of Florida, Gainesville
• DOE Contract Number: AI01-81ER60001
• OSTI ID: 5768141
• Journal Information: Crop Sci.; (United States), Journal Name: Crop Sci.; (United States) Vol. 25:2; ISSN CRPSA
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
560303 -- Chemicals Metabolism & Toxicology-- Plants-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AIR POLLUTION
BIOLOGICAL ACCUMULATION
BIOLOGICAL ADAPTATION
BIOLOGICAL EFFECTS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON DIOXIDE FIXATION
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
GLYCINE HISPIDA
LEAVES
LEGUMINOSAE
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOSYNTHESIS
PLANTS
POLLUTION
RADIATIONS
SYNTHESIS
VISIBLE RADIATION