Metabolite levels in the chloroplast and extrachloroplast compartments of barley leaf protoplasts during the initial phase of photosynthetic induction

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Abstract

Metabolite levels were determined in the chloroplast and extrachloroplast compartments of barley protoplasts during photosynthetic induction using rapid fractionation by membrane filtration. This method allowed studies with a high time resolution - the first determination of subcellular metabolite content bring made after only 0.3 s. Upon illumination, dark-adapted protoplasts exhibited a 1 min lag phase prior to commencement of oxygen evolution, and the maximum rate was reached after 4 to 5 min. In contrast to oxygen evolution, the ATP/ADP ratio in the chloroplasts increased from 1 to 2 within 0.5 s and reached a maximum of about 5 after 2 s. There was a dramatic increase in the extrachloroplastic ATP/ADP ratio within a few seconds, reaching a maximum after about 15 s. During the initial phase of photosynthetic induction, the subcellular ATP/ADP ratios were very similar in photorespiratory (low CO2) and non-photorespiratory (high CO2) conditions. The ATP/ADP ratios in both the chloroplast and extrachloroplast compartments remained high until photosynthetic oxygen evolution started and then decreased when the photosynthetic rate reached its maximum. In steady-state photosynthesis the subcellular ATP/ADP ratios were considerably higher under photorespiratory conditions as compared to non-photorespiratory conditions. During the initial phase of photosynthetic induction, 3-phosphoglycerate decreased and triose phosphates increased both in the chloroplast and extrachloroplast compartments. The changes in these metabolites are consistent with a 3-phosphoglycerate/triose phosphate shuttle using the phosphate translocator as the means to supply ATP to the cytosol during photosynthetic induction.

References (43)

  • M. Stitt et al.

    J. Plant Physiol.

    (1988)
  • M. Stitt et al.

    J. Plant Physiol.

    (1988)
  • R.T. Prinsley et al.

    Biochim. Biophys. Acta

    (1986)
  • W.P. Quick et al.

    Biochim. Biophys. Acta

    (1986)
  • M. Stitt et al.

    J. Plant Physiol.

    (1988)
  • K.A. Santarius et al.

    Biochim. Biophys. Acta

    (1965)
  • K.-J. Dietz et al.

    Biochim. Biophys. Acta

    (1984)
  • P. Gardeström

    FEBS Lett.

    (1987)
  • J. Bruinsma

    Biochim. Biophys. Acta

    (1961)
  • R. Fliege et al.

    Biochim. Biophys. Acta

    (1978)
  • G. Woldegiorgis et al.

    Biochim. Biophys. Acta

    (1985)
  • R.T. Furbank et al.

    Biochem. Biophys. Acta

    (1987)
  • S. Krömer et al.

    FEBS Lett.

    (1988)
  • S. Krömer et al.

    Biochim. Biophys. Acta

    (1991)
  • G.F. Sassenrath-Cole et al.

    Plant Physiol.

    (1992)
  • S. Rumich-Bayer et al.

    Photosynth. Res.

    (1986)
  • B.B. Buchanan

    Annu. Rev. Plant Physiol.

    (1980)
  • K. Siebke et al.

    Planta

    (1991)
  • M.E. Salvucci

    Physiol. Plant.

    (1989)
  • R.C. Leegood et al.

    Plant Cell Env.

    (1981)
  • D.A. Walker et al.

    Photobiochem. Photobiophys.

    (1983)
  • Cited by (0)

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