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. 1992 Aug;99(4):1309–1313. doi: 10.1104/pp.99.4.1309

Fluorescence Quenching in the Varied Photosynthetic Modes of Portulacaria afra (L.) Jacq. 1

Lonnie J Guralnick 1,2,3, Robert L Heath 1,2,3, Guillermo Goldstein 1,2,3, Irwin P Ting 1,2,3
PMCID: PMC1080625  PMID: 16669037

Abstract

The kinetics of chlorophyll fluorescence were measured in Portulacaria afra (L.) Jacq. when the plants were functioning in either Crassulacean acid metabolism (CAM) or C3/CAM cycling (called cycling) modes, as determined by fluctuation in titratable acidity and gas exchange properties. Cycling plants showed primarily daytime CO2 uptake typical of C3 plants, but with a slight diurnal acid fluctuation, whereas CAM plants showed nocturnal CO2 uptake, daytime stomatal closure, and a large diurnal acid fluctuation. Results from fluorescence measurements indicated no significant differences in photochemical quenching between cycling and CAM plants; however, sizable differences were detected in nonphoto-chemical quenching (qn), with the largest differences being observed during the middle of the day. Cycling plants had lower qn than CAM plants, indicating altered photosynthetic regulation processes. This qn difference was believed to be related to reduced internal CO2 concentration in the CAM plants because of daytime stomatal closure and reduced deacidification rates in the late afternoon when most of the malic acid has been utilized. Experimentally, higher external CO2 given to plants in the CAM mode resulted in a decline in qn in comparison to that measured in plants in the cycling mode. No changes were observed in photochemical quenching when CO2 was added.

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Selected References

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

  1. Cockburn W. Relationships between Stomatal Behavior and Internal Carbon Dioxide Concentration in Crassulacean Acid Metabolism Plants. Plant Physiol. 1979 Jun;63(6):1029–1032. doi: 10.1104/pp.63.6.1029. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Everson G., Chen S. S., Black C. C. Diurnal variations in leaf fluorescence induction kinetics: variable fluorescence in crassulacean Acid metabolism plants. Plant Physiol. 1983 Jun;72(2):455–460. doi: 10.1104/pp.72.2.455. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Guralnick L. J., Rorabaugh P. A., Hanscom Z. Influence of Photoperiod and Leaf Age on Crassulacean Acid Metabolism in Portulacaria afra (L.) Jacq. Plant Physiol. 1984 Jun;75(2):454–457. doi: 10.1104/pp.75.2.454. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Guralnick L. J., Rorabaugh P. A., Hanscom Z. Seasonal Shifts of Photosynthesis in Portulacaria afra (L.) Jacq. Plant Physiol. 1984 Nov;76(3):643–646. doi: 10.1104/pp.76.3.643. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Hanscom Z., Ting I. P. Responses of succulents to plant water stress. Plant Physiol. 1978 Mar;61(3):327–330. doi: 10.1104/pp.61.3.327. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Köster S., Winter K. Light Scattering as an Indicator of the Energy State in Leaves of the Crassulacean Acid Metabolism Plant Kalanchoë pinnata. Plant Physiol. 1985 Oct;79(2):520–524. doi: 10.1104/pp.79.2.520. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Peterson R. B., Sivak M. N., Walker D. A. Relationship between Steady-State Fluorescence Yield and Photosynthetic Efficiency in Spinach Leaf Tissue. Plant Physiol. 1988 Sep;88(1):158–163. doi: 10.1104/pp.88.1.158. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Winter K., Demmig B. Reduction State of Q and Nonradiative Energy Dissipation during Photosynthesis in Leaves of a Crassulacean Acid Metabolism Plant, Kalanchoë daigremontiana Hamet et Perr. Plant Physiol. 1987 Dec;85(4):1000–1007. doi: 10.1104/pp.85.4.1000. [DOI] [PMC free article] [PubMed] [Google Scholar]

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