Photosynthetic plasticity in Flaveria brownii: Growth irradiance and the expression of C sub 4 photosynthesis

Journal Article · Sat Apr 01 00:00:00 EST 1989 · Plant Physiology; (USA)

DOI:https://doi.org/10.1104/pp.89.4.1129· OSTI ID:6625458

Cheng, Shuhua; Moore, B D; Wu, Jingrui; Edwards, G E; Ku, M S.B. ^[1]

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1. Washington State Univ., Pullman (USA)

Photosynthesis was examined in leaves of Flaveria brownii A. M. Powell, grown under either 14% or 100% full sunlight. In leaves of high light grown plants, the CO{sub 2} compensation point and the inhibition of photosynthesis by 21% O{sub 2} were significantly lower, while activities of ribulose 1,5-bisphosphate carboxylase/oxygenase and various C{sub 4} cycle enzymes were considerably higher than those in leaves grown in low light. Both the CO{sub 2} compensation point and the degree of O{sub 2} inhibition of apparent photosynthesis were relatively insensitive to the light intensity used during measurements with plants from either growth conditions. Partitioning of atmospheric CO{sub 2} between Rubisco of the C{sub 3} pathway and phosphoenolpyruvate carboxylase of the C{sub 4} cycle was determined by exposing leaves to {sup 14}CO{sub 2} for 3 to 16 seconds, and extrapolating the labeling curves of initial products to zero time. Results indicated that {approximately}94% of the CO{sub 2} was fixed by the C{sub 4} cycle in high light grown plants, versus {approximately}78% in low light grown plants. Consistent with the carbon partitioning patterns, photosynthetic enzyme activities (on a chlorophyll basis) in protoplasts from leaves of high light grown plants showed a more C{sub 4}-like pattern of compartmentation. Pyruvate,Pi dikinase and phosphoenolpyruvate carboxylase were more enriched in the mesophyll cells, while NADP-malic enzyme and ribulose 1,5-bisphosphate carboxylase/oxygenase were relatively more abundant in the bundle sheath cells of high light than of low light grown plants.

• OSTI ID: 6625458
• Journal Information: Plant Physiology; (USA), Vol. 89:4; ISSN 0032-0889
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
59 BASIC BIOLOGICAL SCIENCES
C4 SPECIES
BIOLOGICAL PATHWAYS
CARBON DIOXIDE FIXATION
RIBULOSE DIPHOSPHATE CARBOXYLASE
ENZYME ACTIVITY
CARBON 14 COMPOUNDS
CARBON DIOXIDE
OXYGEN
PHOTOSYNTHESIS
PLANT GROWTH
TRACER TECHNIQUES
CARBON COMPOUNDS
CARBON OXIDES
CARBON-CARBON LYASES
CARBOXY-LYASES
CHALCOGENIDES
CHEMICAL REACTIONS
ELEMENTS
ENZYMES
GROWTH
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LYASES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
PLANTS
SYNTHESIS
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
550501 - Metabolism- Tracer Techniques