Xue 1996 Plant Physiol
|Xue X, Gauthier DA, Turpin DH, Weger HG (1996) Interactions between photosynthesis and respiration in the green alga Chlamydomonas reinhardtii. Characterization of light-enhanced dark respiration. Plant Physiol 112:1005–14. https://doi.org/10.1104/pp.112.3.1005|
Abstract: The rate of respiratory O2 consumption by Chlamydomonas reinhardtii cell suspensions was greater after a period of photosynthesis than in the preceding dark period. This “light-enhanced dark respiration” (LEDR) was a function of both the duration of illumination and the photon fluence rate. Mass spectrometric measurements of gas exchange indicated that the rate of gross respiratory O2 consumption increased during photosynthesis, whereas gross respiratory CO2 production decreased in a photon fluence rate-dependent manner. The rate of postillumination O2 consumption provided a good measure of the O2 consumption rate in the light. LEDR was substantially decreased by the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea or glycolaldehyde, suggesting that LEDR was photosynthesis-dependent. The onset of photosynthesis resulted in an increase in the cellular levels of phosphoglycerate, malate, and phosphoenolpyruvate, and a decrease in whole-cell ATP and citrate levels; all of these changes were rapidly reversed upon darkening. These results are consistent with a decrease in the rate of respiratory carbon flow during photosynthesis, whereas the increase in respiratory O2 consumption during photosynthesis may be mediated by the export of photogenerated reductant from the chloroplast. We suggest that photosynthesis interacts with respiration at more than one level, simultaneously decreasing the rate of respiratory carbon flow while increasing the rate of respiratory O2 consumption.
• Bioblast editor: Gnaiger E
- At the highest PFR (photon fluence rate), temperatures inside the cuvette changed less than 0.08 °C.
- LEDR of dark-adapted cells was a function of both the PFR and the time of illumination.
- Preincubation of cell suspensions with inhibitors of photosynthesis (5 µM DCMU or 10 mM glycolaldehyde) also decreased the magnitude of LEDR. - DCMU is an inhibitor of the non-cyclic electron flow after the primary electron acceptor of PSII, but cyclic electron flow around PSI is still possible in the presence of this compound (Trebst, 1980). Glycolaldehyde is a Calvin cycle inhibitor that prevents the regeneration of ribulose-1,5-bisphosphate from triose phosphate (Sicher, 1984).
- Red, blue, and control light (tungsten halogen light source) were approximately equivalent in powering LEDR.
- The contribution of the alternative respiratory pathway to LEDR was examined by the use of the alternative oxidase inhibitor propyl gallate (Weger and Dasgupta, 1993). Addition of propyl gallate, added pre- or postillumination, had no effect on the postillumination O2 consumption rates.
- Went N, Di Marcello M, Gnaiger E (2021) Oxygen dependence of photosynthesis and light-enhanced dark respiration studied by High-Resolution PhotoRespirometry. MitoFit Prep 2021.5. - »Bioblast link«
Labels: MiParea: Respiration
LEDR, Photosynthesis, MitoFit 2021.5 PB