Limiting factors in photosynthesis. V. Photochemical energy supply colimits photosynthesis at low values of intercellular CO/sub 2/ concentration

Journal Article · Tue May 01 00:00:00 EDT 1984 · Plant Physiol.; (United States)

OSTI ID:6137736

Taylor, S E; Terry, N

Although there is now some agreement with the view that the supply of photochemical energy may influence photosynthetic rate (P) at high CO/sub 2/ pressures, it is less clear whether this limitation extends to P at low CO/sub 2/. This was investigated by measuring P per area as a function of the intercellular CO/sub 2/ concentration (C/sub i/) at different levels of photochemical energy supply. Changes in the latter were obtained experimentally by varying the level of irradiance to normal (Fe-sufficient) leaves of Beta vulgaris L. cv F58-554H1, and by varying photosynthetic electron transport capacity using leaves from Fe-deficient and Fe-sufficient plants. P and C/sub i/ were determined for attached sugar beet leaves using open flow gas exchange. The results suggest the P/area was colimited by the supply of photochemical energy at very low as well as high values of C/sub i/. Using the procedure developed by Perchorowicz et al., we investigated the effect or irradiance on ribulose bisphosphate carboxylase (RuBPCase) activation. The ratio of initial extractable activity to total inducible RuBPCase activity increased from 0.25 to 0.90 as leaf irradiance increased from 100 to 1500 microeinsteins photosynthetically active radiation per square meter per second. These data suggest that colimitation by photochemical energy supply at low C/sub i/ may be mediated via effects on RuBPCase activation.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 6137736
• Journal Information: Plant Physiol.; (United States), Vol. 75:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
14 SOLAR ENERGY
CARBOXYLASE
ENZYME ACTIVITY
PHOTOSYNTHESIS
BIOCHEMICAL REACTION KINETICS
CARBON DIOXIDE
ELECTRON TRANSFER
IRON
LEAVES
LIMITING VALUES
VISIBLE RADIATION
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENZYMES
KINETICS
LIGASES
METALS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
REACTION KINETICS
SYNTHESIS
TRANSITION ELEMENTS
550200* - Biochemistry
140505 - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)