Photosynthesis Research

, Volume 35, Issue 3, pp 265–274 | Cite as

Light dependence of quantum yields of Photosystem II and CO2 fixation in C3 and C4 plants

  • Walter Oberhuber
  • Zi-Yu Dai
  • Gerald E. Edwards
Regular Paper


The light dependence of quantum yields of Photosystem II (ΦII) and of CO2 fixation were determined in C3 and C4 plants under atmospheric conditions where photorespiration was minimal. Calculations were made of the apparent quantum yield for CO2 fixation by dividing the measured rate of photosynthesis by the absorbed light [A/I=ΦCO2 and of the true quantum yield by dividing the estimated true rate of photosynthesis by absorbed light [(A+Rl)/IaCO2·], where RL is the rate of respiration in the light. The dependence of the ΦIICO2 and ΦIICO2* ratios on light intensity was then evaluated. In both C3 and C4 plants there was little change in the ratio of ΦIICO2 at light intensities equivalent to 10–100% of full sunlight, whereas there was a dramatic increase in the ratio at lower light intensities. Changes in the ratio of ΦIICO2 can occur because respiratory losses are not accounted for, due to changes in the partitioning of energy between photosystems or changes in the relationship between PS II activity and CO2 fixation. The apparent decrease in efficiency of utilization of energy derived from PS II for CO2 fixation under low light intensity may be due to respiratory loss of CO2. Using dark respiration as an estimate of RL, the calculated ΦIICO2* ratio was nearly constant from full sunlight down to approx 5% of full sunlight, which suggests a strong linkage between the true rate of CO2 fixation and PS II activity under varying light intensity. Measurements of photosynthesis rates and ΦII were made by illuminating upper versus lower leaf surfaces of representative C3 and C4 monocots and dicots. With the monocots, the rate of photosynthesis and the ratio of ΦIICO2 exhibited a very similar patterns with leaves illuminated from the adaxial versus the abaxial surface, which may be due to uniformity in anatomy and lack of differences in light acclimation between the two surfaces. With dicots, the abaxial surface had both lower rates of photosynthesis and lower ΦII values than the adaxial surface which may be due to differences in anatomy (spongy versus palisade mesophyll cells) and/or light acclimation between the two surfaces. However, in each species the response of ΦIICO2 to varying light intensity was similar between the two surfaces, indicating a comparable linkage between PS II activity and CO2 fixation.

Key words

C3 plants C4 plants light Photosystem II quantum yield fluorescence 



measured rate of CO2 assimilation


true rate of CO2 assimilation; e


estimate of electrons transported through PSII per CO2 fixed by RuBP carboxylase


fraction of light absorbed by Photosystem II


yield of PSII chlorophyll α fluorescence due to a saturating flash of white light under steady-state photosynthesis


variable yield of fluorescence under steady-state photosynthesis; PPFD-photosynthetic photon flux density


absorbed PPFD


Photosystem II


rate of respiration in the dark


rate of respiration in the light estimated from measurement of Rd or from analysis of quantum yields


apparent quantum yield of CO2 assimilation under a given condition (A/absorbed PPFD)


true quantum yield of CO2 assimilation under a given condition [(A+RL)/(absorbed PPFD)]


quantum yield for photosynthetic O2 evolution


electrons transported via PS II per quantum absorbed by PS II


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  1. Baker NR (1991) A possible role for Photosystem II in environmental perturbations of photosynthesis. Physiol Plant 81: 563–570Google Scholar
  2. Brooks A and Farquhar GD (1985) Effect of temperature on the CO2/O2 specificity of ribulose-1,5-bisphosphate carboxylase/oxygenase and the rate of respiration in the light. Planta 165: 397–406Google Scholar
  3. Brown RH and Hattersley PW (1989) Leaf anatomy of C3-C4 species as related to evolution of C4 photosynthesis. Plant Physiol 91: 1543–1550Google Scholar
  4. Brugnoli E and Bjorkman O (1992) Chloroplast movements in leaves: Influence on chlorophyll fluorescence and measurements of light-induced absorbance changes related to ΔpH and zeaxanthin formation. Photosynth Res 32: 23–35Google Scholar
  5. Cornic G and Briantais JM (1991) Partitioning of photosynthetic electron flow between CO2 and O2 reduction in a C3 leaf (Phaseolus vulgaris L.) at different CO2 concentrations and during drought stress. Planta 183: 178–184Google Scholar
  6. Edwards GE and Walker DA (1983) C3, C4 Photosynthesis: Mechanisms, and Cellular, and Environmental Regulation of Photosynthesis. Blackwell Sci Publ, Oxford, 542 ppGoogle Scholar
  7. Genty B, Briantais J-M and Baker NR (1989) The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence. Biochim Biophys Acta 990: 87–92Google Scholar
  8. Harbinson J, Genty B and Baker NR (1990) The relationship between CO2 assimilation and electron transport in leaves. Photosynth Res 25: 213–224Google Scholar
  9. Jelling AJ and Leech RM (1984) Anatomical variation in first leaves of nine Triticum genotypes, and its relationship to photosynthetic capacity. New Phyto 96: 371–382Google Scholar
  10. Krall JP and Edwards GE (1990) Quantum yields of Photosystem II electron transport and carbon dioxide fixation in C4 plants. Aust J Plant Physiol 17: 579–588Google Scholar
  11. Krall JP and Edwards GE (1992) Relationship between Photosystem II activity and CO2 fixation in leaves. What's New in Plant Physiology. Physiol Plant 86: 180–187CrossRefGoogle Scholar
  12. Krause GH and Weis E (1991) Chlorophyll fluorescence and photosynthesis: The basics. Annu Rev Plant Physiol Plant Mol Biol 42: 313–349CrossRefGoogle Scholar
  13. Moss DN (1964) Optimum lighting of leaves. Crop Sci 4: 131–136Google Scholar
  14. Öquist G and Chow WS (1992) On the relationship between the quantum yield of Photosystem II electron transport, as determined by chlorophyll fluorescence and the quantum yield of CO2-dependent O2 evolution. Photosynth Res 33: 51–62Google Scholar
  15. Peterson RB (1989) Partitioning of noncyclic photosynthetic electron transport to O2-dependent dissipative processes as probed by fluorescence and CO2 exchange. Plant Physiol 90: 1322–1328Google Scholar
  16. Seaton GR and Walker DA (1990) Chlorophyll fluorescence as a measure of photosynthetic carbon assimilation. Philos Trans R Soc Lond B 242: 29–35Google Scholar
  17. Sharkey TD, Berry JA and Sage RF (1988) Regulation of photosynthetic electron-transport in Phaseolus vulgaris L., as determined by room-temperature chlorophyll α fluorescence. Planta 176: 415–424Google Scholar
  18. Sharp RE, Matthews MA and Boyer JS (1984) Kok effect and the quantum yield of photosynthesis. Light partially inhibits dark respiration. Plant Physiol 75: 95–101Google Scholar
  19. Terashima I and Inoue Y (1985a) Palisade tissue chloroplasts and spongy tissue chloroplasts in spinach: Biochemical and ultrastructural differences. Plant Cell Physiol 26: 63–75Google Scholar
  20. Terashima I and Inoue Y (1985b) Vertical gradient in photosynthetic properties of spinach chloroplasts dependent on intra-leaf light environment. Plant Cell Physiol 26: 781–785Google Scholar
  21. Terashima I and Takenaka A (1990) Factors determining light response characteristics of leaf photosynthesis. In: Baltscheffsky M (ed) Current Research in Photosynthesis, Vol IV, pp 299–306. Kluwer Academic Publishers, DordrechtGoogle Scholar
  22. vanKooten O and Snel JFH (1990) The use of chlorophyll fluorescence nomenclature in plant stress physiology. Photosynth Res 25: 147–150Google Scholar
  23. vonCaemmerer S and Farquhar GD (1981) Some relationships between the biochemistry of photosynthesis and the gas exchange of leaves. Planta 153: 376–387Google Scholar
  24. Walter-Shea EA and Norman JM (1991) Leaf optical properties. In: Myneni RB and Ross J (eds) Photon Vegetation Interactions, pp 227–251. Springer-Verlag, New YorkGoogle Scholar

Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • Walter Oberhuber
    • 1
  • Zi-Yu Dai
    • 1
  • Gerald E. Edwards
    • 1
  1. 1.Department of BotanyWashington State UniversityPullmanUSA

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