Abstract
The hypothesis is tested that acidification of the bulk medium during transplasmalemma electron transport to ferricyanide is due solely to a requirement for charge balance. According to this hypothesis, reduction of the trivalent anion, ferricyanide, to the tetravalent anion, ferrocyanide, results in a charge difference that is balanced by protons. A coulometric device is used that rapidly and efficiently reoxidizes ferrocyanide to ferricyanide, thus maintaining a constant charge in the bulk medium. Oat (Avena sativa L. cv Garry) mesophyll protoplasts are chosen as experimental material to facilitate ferricyanide reduction and the concomitant ferrocyanide reoxidation by the coulometric device. The kinetics of ferricyanide reduction and proton excretion by protoplasts are similar to those of other cell types and tissues. Rates of net proton excretion are identical regardless of whether the ferrocyanide is simultaneously reoxidized. We conclude that acidification may occur during transplasmalemma electron transport when there is no change in negative charge of the bulk medium.
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Selected References
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- Böttger M., Hilgendorf F. Hormone action on transmembrane electron and h transport. Plant Physiol. 1988 Apr;86(4):1038–1043. doi: 10.1104/pp.86.4.1038. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kelly B. M. Light-Stimulated Changes in the Acidity of Suspensions of Oat Protoplasts: Dependence upon Photosynthesis. Plant Physiol. 1983 Jun;72(2):351–355. doi: 10.1104/pp.72.2.351. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Marrè M. T., Moroni A., Albergoni F. G., Marrè E. Plasmalemma redox activity and h extrusion: I. Activation of the h-pump by ferricyanide-induced potential depolarization and cytoplasm acidification. Plant Physiol. 1988 May;87(1):25–29. doi: 10.1104/pp.87.1.25. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rubinstein B., Stern A. I. Relationship of Transplasmalemma Redox Activity to Proton and Solute Transport by Roots of Zea mays. Plant Physiol. 1986 Apr;80(4):805–811. doi: 10.1104/pp.80.4.805. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rubinstein B. Use of lipophilic cations to measure the membrane potential of oat leaf protoplasts. Plant Physiol. 1978 Dec;62(6):927–929. doi: 10.1104/pp.62.6.927. [DOI] [PMC free article] [PubMed] [Google Scholar]