Abstract
Kinetically-resolved absorbance measurements during extended, or steady-state illumination are typically hindered by large, light-induced changes in the light-scattering properties of the material. In this work, a new type of portable spectrophotometer, the Non-Focusing Optical Spectrophotometer (NoFOSpec), is introduced, which reduces interference from light-scattering changes and is in a form suitable for fieldwork. The instrument employs a non-focusing optical component, called a compound parabolic concentrator (CPC), to simultaneously concentrate and homogeneously diffuse measuring and actinic light (from light-emitting diode sources) onto the leaf sample. Light passing through the sample is then collected and processed using a subsequent series of CPCs leading to a photodiode detector. The instrument is designed to be compact, lightweight and rugged for field work. The pulsed measuring beam allows for high sensitivity (typically < 100 ppm noise) and time resolution (∼ 10 μs) measurements in the visible and near infrared spectral regions. These attributes allow high-resolution measurements of signals associated with energization of the thylakoid membrane (the electrochromic shifting of carotenoid pigments), as well as electron transfer, e.g., the 820-nm changes associated with electron transfer through Photosystem I (PS I). In addition, the instrument can be used as a kinetic fluorimeter, e.g., to measure saturation-pulse fluorescence changes indicative of Photosystem II (PS II) quantum efficiency. The instrument is demonstrated by estimating electron and proton fluxes through the photosynthetic apparatus in an intact tobacco leaf, using respectively the saturation-pulse fluorescence changes and dark-interval relaxation kinetics (DIRK) of the electrochromic shift. A linear relationship was found, confirming our earlier results with the laboratory-based diffused-optics flash spectrophotometer, indicating a constant H+/e− stoichiometry for linear electron transfer, and suggesting that cyclic electron flow around PS I is either negligible or proportional to linear electron flow. This type of measurement should be useful under field conditions for estimating the extent of PS I cyclic electron transfer, which is proposed to operate under stressed conditions.
Similar content being viewed by others
References
Asada K (1996) Radical production and scavenging in the chloroplasts. In: Baker NR (ed) Photosynthesis and the Environment, pp 123–150. Kluwer Academic Publishers, Dordrecht, The Netherlands
Baker NR (1996) Environmental constraints on photosynthesis: an overview of some future prospects. In: Baker NR (ed) Photosynthesis and the Environment, pp 469–476. Kluwer Academic Publishers, Dordrecht, The Netherlands
Baker NR and Bowyer JR (1994) Photoinhibition of photosynthesis from molecular mechanisms to the field. In: Davies WJ (ed) Environmental Plant Biology, pp 1–471. Bios Scientific Publishers, Lancaster, UK
Baker NR, Oxborough K and Andrews JR (1995) Operation of an alternate electron transfer acceptor to CO2 in maize crops during periods of low temperatures. In: Mathis P (ed) Photosynthesis: From Light to Biosphere, pp 771–776. Kluwer Academic Publishers, Dordrecht, The Netherlands
Bolhàr-Nordenkampf HR and Öquist G (1993) Chlorophyll fluorescence as a tool in photosynthesis research. In: Hall DO, Scurlock JMO, Bolhàr-Nordenkampf HR, Leegood RC and Long SP (ed) Photosynthesis and Production in a Changing Environment: A Field and Laboratory Manual, pp 193–206. Chapman & Hall, London
Cruz JA, Sacksteder CA, Kanazawa A and Kramer DM (2000) Contribution of electric field (△ψ) to steady-state transthylakoid proton motive force itin vitro and in vivo. Control of pmf parsing into △? and △pH by counterion fluxes. Biochemistry 40:1226–1237
Edwards GE and Baker NR (1993) Can CO2 assimilation in maize leaves be predicted accurately from chlorophyll fluorescence analysis? Photosynth Res 37: 89–102
Foyer C, Furbank R, Harbinson J and Horton P (1990) The mechanisms contributing to photosynthetic control of electron transport by carbon assimilation in leaves. Photosynth Res 25: 83–100
Foyer CH, Lelandais M and Harbinson J (1992) Control of the quantum efficiencies of photosystems I and II, electron flow, and enzyme activation following dark-to-light transitions in pea leaves. Plant Physiol 99: 979–986
Genty B and Harbinson J (1996) Regulation of light utilization for photosynthetic electron transport. In: Baker NR (ed) Photosynthesis and the Environment, pp 67–99. Kluwer Academic Publishers, Dordrecht, The Netherlands
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: 87–92
Genty B, Harbinson J and Baker NR (1990) Relative quantum ef-ficiencies of Photosystems I and II of leaves in photorespiratory and non-photorespiratory conditions. Plant Physiol Biochem 28: 1–10
Harbinson J and Foyer CH (1991) Relationships between the ef-ficiencies of photosystems I and II and stromal redox state in CO2-free air. Evidence for cyclic electron transfer in vivo. Plant Physiol 97: 41–49
Harbinson J, Genty B and Baker NR (1989) Relationship between the quantum efficiencies of Photosystem I and II in pea leaves. Plant Physiol 90: 1029–1034
Harbinson J, Genty B and Foyer CH (1990) Relationship between photosynthetic electron transport and stromal enzyme activity in pea leaves. Plant Physiol 94: 545–553
Havaux M and Davaud A (1994) Photoinhibition of photosynthesis in chilled potato leaves is not correlated with a loss of Photosystem-II activity. Preferential inactivation of Photosystem I. Photosynth Res 40: 75–92
Heber U and Walker D (1992) Concerning a dual function of coupled cyclic electron transport in leaves. Plant Physiol 100: 1621–1626
Heber U, Gerst U, Krieger A, Neimanis S and Kobayashi Y (1995) Coupled cyclic electron transport in intact chloroplasts and leaves of C3 plants: Does it exist? If so, what is its function? Photosynth Res 46: 269–275
Hipkins MF and Baker NR (1986)Photosynthesis: Energy Transduction, A Practical Approach. IRL Press Limited, Oxford, Washington, DC
Joliot P and Joliot A (1984) Electron transfer between the two photosystems. I. Flash excitation under oxidizing conditions. Biochim Biophys Acta 765: 210–218
Kanazawa A, Kiirats O, Edwards G, Cruz J and Kramer DM (2001) New steps in the regulation of photosynthesis: The influence of CFO-CF1 ATP synthase conductivity on the sensitivity of antenna down-regulation. In:Critchley C (ed) Proceedings of the XIIth International Congress on Photosynthesis (in press)
Klughammer C and Schreiber U (1994) An improved method, using saturating light pulses, for the determination of Photosystem I quantum yield via P700+ absorbance changes at 830 nm. Planta 192: 261–268
Klughammer C, Kolbowski J and Schreiber U (1990) LED array spectrophotometer for measurement of time resolved difference spectra in the 530-600 nm wavelength region. Photosynth Res 25: 317–327
Kramer DM and Crofts AR (1996) Control of photosynthesis and measurement of photosynthetic reactions in intact plants. In: Baker N (ed) Photosynthesis and the Environment. Advances in Photosynthesis, pp 25–66. Kluwer Academic Publishers, Dordrecht, The Netherlands
Kramer DM and Sacksteder CA (1998) A diffused-optics flash kinetic spectrophometer (DOFS) for measurements of absorbance changes in intact plants in the steady-state. Photosynth Res 56: 103–112
Kramer DM, Sacksteder CA and Cruz JA (1999) How acidic is the lumen? Photosynth Res 60: 151–163
Long SP and Hällgren JE (1993) Measurement of CO2assimilation by plants in the field and the laboratory. In: Hall DO, Scurlock JMO, Bolhàr-Nordenkampf HR, Leegood RC and Long SP (ed) Photosynthesis and Production in a Changing Environment: A Field and Laboratory Manual, pp 129–167. Chapman & Hall, London
McCree KJ (1972) The action spectrum, absorptance and quantum yield of photosynthesis in crop plants. Agric Meteorol 9: 191–216
Peterson RB (1991) Effects of O2 and CO2 concentrations on quantum yields of Photosystem I and II in tobacco leaf tissue. Plant Physiol 97: 1388–1394
Sacksteder CA and Kramer DM (2000a) Dark-interval relaxation kinetics (DIRK) of absorbance changes as a quantitative probe of steady-state electron transfer. Photosynth Res 66: 145–158
Sacksteder CA and Kramer DM (2000b) The proton to electron stoichiometry of steady-state photosynthesis in living plants: A proton-pumping Q-cycle is continuously engaged. Proc Natl Acad Sci USA 97: 14283–14288
Sonoike K (1996) Photoinhibition of Photosystem I: Its physiological significance in the chilling sensitivity of plants. Plant Cell Physiol 37: 239–247
Sonoike K (1999a) The different roles of chilling temperatures in the photoinhibition of Photosystem I and Photosystem II. J Photochem Photobiol B 48: 136–142
Sonoike K (1999b) The different roles of chilling temperatures in the photoinhibition of Photosystem I and Photosystem II. J. Photochem Photobiol B 48: 136–142
Styring S, Virgin I, Ehrenberg A and Andersson B (1990) Strong light photoinhibition of electron transport in Photosystem II. Impairment of the function of the first quinone acceptor, QA. Biochim Biophys Acta 1015: 269
Tjus SE, Moller BL and Scheller HV (1998) Photosystem I is an early target of photoinhibition in barley illuminated at chilling temperatures. Plant Physiol 116: 755–765
von Caemmerer S and Farquhar GD (1981) Some relationships between the biochemistry of photosynthesis and the gas exchange of leaves. Planta 153: 376–387
Weiss E, Lechtenburg D and Krieger A (1990) Physiological control of primary photochemical energy in higher plants. In: Baltscheffsky M (ed) Current Research in Photosynthesis, pp 307–312. Kluwer Academic Publishers, Dordrecht, The Netherlands
Welford WT and Winston R (1989) High Collection Nonimaging Optics. Academic Press, San Diego, California
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Sacksteder, C.A., Jacoby, M.E. & Kramer, D.M. A portable, non-focusing optics spectrophotometer (NoFOSpec) for measurements of steady-state absorbance changes in intact plants. Photosynthesis Research 70, 231–240 (2001). https://doi.org/10.1023/A:1017906626288
Issue Date:
DOI: https://doi.org/10.1023/A:1017906626288