Skip to main content
NCBI home page
Plant Physiology logoLink to Plant Physiology
. 1988 Nov;88(3):757–763. doi: 10.1104/pp.88.3.757

Characterization of the Na+-Requirement in Cyanobacterial Photosynthesis 1

George S Espie 1, Anthony G Miller 1, David T Canvin 1
PMCID: PMC1055656  PMID: 16666379

Abstract

The Na+ requirement for photosynthesis and its relationship to dissolved inorganic carbon (DIC) concentration and Li+ concentration was examined in air-grown cells of the cyanobacterium Synechococcus leopoliensis UTEX 625 at pH 8. Analysis of the rate of photosynthesis (O2 evolution) as a function of Na+ concentration, at fixed DIC concentration, revealed two distinct regions to the response curve, for which half-saturation values for Na+ (K½[Na+]) were calculated. The value of both the low and the high K½(Na+) was dependent upon extracellular DIC concentration. The low K½(Na+) decreased from 1000 micromolar at 5 micromolar DIC to 200 micromolar at 140 micromolar DIC whereas over the same DIC concentration range the high K½(Na+) decreased from 10 millimolar to 1 millimolar. The most significant increases in photosynthesis occurred in the 1 to 20 millimolar range. A fraction of total photosynthesis, however, was independent of added Na+ and this fraction increased with increased DIC concentration. A number of factors were identified as contributing to the complexity of interaction between Na+ and DIC concentration in the photosynthesis of Synechococcus. First, as revealed by transport studies and mass spectrometry, both CO2 and HCO3− transport contributed to the intracellular supply of DIC and hence to photosynthesis. Second, both the CO2 and HCO3− transport systems required Na+, directly or indirectly, for full activity. However, micromolar levels of Na+ were required for CO2 transport while millimolar levels were required for HCO3− transport. These levels corresponded to those found for the low and high K½(Na+) for photosynthesis. Third, the contribution of each transport system to intracellular DIC was dependent on extracellular DIC concentration, where the contribution from CO2 transport increased with increased DIC concentration relative to HCO3− transport. This change was reflected in a decrease in the Na+ concentration required for maximum photosynthesis, in accord with the lower Na+-requirement for CO2 transport. Lithium competitively inhibited Na+-stimulated photosynthesis by blocking the cells' ability to form an intracellular DIC pool through Na+-dependent HCO3− transport. Lithium had little effect on CO2 transport and only a small effect on the size of the pool it generated. Thus, CO2 transport did not require a functional HCO3− transport system for full activity. Based on these observations and the differential requirement for Na+ in the CO2 and HCO3− transport system, it was proposed that CO2 and HCO3− were transported across the membrane by different transport systems.

Full text

PDF
757

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Badger M. R., Andrews T. J. Photosynthesis and Inorganic Carbon Usage by the Marine Cyanobacterium, Synechococcus sp. Plant Physiol. 1982 Aug;70(2):517–523. doi: 10.1104/pp.70.2.517. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Brownell P. F., Nicholas D. J. Some Effects of Sodium on Nitrate Assimilation and N(2) Fixation in Anabaena cylindrica. Plant Physiol. 1967 Jul;42(7):915–921. doi: 10.1104/pp.42.7.915. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Coleman J. R., Colman B. Inorganic Carbon Accumulation and Photosynthesis in a Blue-green Alga as a Function of External pH. Plant Physiol. 1981 May;67(5):917–921. doi: 10.1104/pp.67.5.917. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Espie G. S., Canvin D. T. Evidence for Na-Independent HCO(3) Uptake by the Cyanobacterium Synechococcus leopoliensis. Plant Physiol. 1987 May;84(1):125–130. doi: 10.1104/pp.84.1.125. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Espie G. S., Miller A. G., Birch D. G., Canvin D. T. Simultaneous Transport of CO(2) and HCO(3) by the Cyanobacterium Synechococcus UTEX 625. Plant Physiol. 1988 Jul;87(3):551–554. doi: 10.1104/pp.87.3.551. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. HOCH G., KOK B. A mass spectrometer inlet system for sampling gases dissolved in liquid phases. Arch Biochem Biophys. 1963 Apr;101:160–170. doi: 10.1016/0003-9861(63)90546-0. [DOI] [PubMed] [Google Scholar]
  7. Maeso E. S., Piñas F. F., Gonzalez M. G., Valiente E. F. Sodium Requirement for Photosynthesis and Its Relationship with Dinitrogen Fixation and the External CO(2) Concentration in Cyanobacteria. Plant Physiol. 1987 Oct;85(2):585–587. doi: 10.1104/pp.85.2.585. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Miller A. G., Canvin D. T. Na-Stimulation of Photosynthesis in the Cyanobacterium Synechococcus UTEX 625 Grown on High Levels of Inorganic Carbon. Plant Physiol. 1987 May;84(1):118–124. doi: 10.1104/pp.84.1.118. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Miller A. G., Espie G. S., Canvin D. T. Active Transport of CO(2) by the Cyanobacterium Synechococcus UTEX 625 : Measurement by Mass Spectrometry. Plant Physiol. 1988 Mar;86(3):677–683. doi: 10.1104/pp.86.3.677. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Miller A. G., Espie G. S., Canvin D. T. Chlorophyll a Fluorescence Yield as a Monitor of Both Active CO(2) and HCO(3) Transport by the Cyanobacterium Synechococcus UTEX 625. Plant Physiol. 1988 Mar;86(3):655–658. doi: 10.1104/pp.86.3.655. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Miller A. G., Turpin D. H., Canvin D. T. Na+ requirement for growth, photosynthesis, and pH regulation in the alkalotolerant cyanobacterium Synechococcus leopoliensis. J Bacteriol. 1984 Jul;159(1):100–106. doi: 10.1128/jb.159.1.100-106.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Ogawa T., Kaplan A. The Stoichiometry between CO(2) and H Fluxes Involved in the Transport of Inorganic Carbon in Cyanobacteria. Plant Physiol. 1987 Apr;83(4):888–891. doi: 10.1104/pp.83.4.888. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Volokita M., Zenvirth D., Kaplan A., Reinhold L. Nature of the Inorganic Carbon Species Actively Taken Up by the Cyanobacterium Anabaena variabilis. Plant Physiol. 1984 Nov;76(3):599–602. doi: 10.1104/pp.76.3.599. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES