Photosynthesis Research

, Volume 114, Issue 2, pp 69-96

First online:

Experimental in vivo measurements of light emission in plants: a perspective dedicated to David Walker

  • Hazem M. KalajiAffiliated withDepartment of Plant Physiology, Faculty of Agriculture and Biology, Warsaw University of Life Sciences SGGW Email author 
  • , Vasilij GoltsevAffiliated withDepartment of Biophysics and Radiobiology, Faculty of Biology St. Kliment Ohridski University of Sofia
  • , Karolina BosaAffiliated withDepartment of Pomology, Faculty of Horticulture and Landscape Architecture, Warsaw University of Life Sciences SGGW
  • , Suleyman I. AllakhverdievAffiliated withInstitute of Plant Physiology, Russian Academy of SciencesInstitute of Basic Biological Problems, Russian Academy of Sciences
  • , Reto J. StrasserAffiliated withBioenergetics Laboratory, University of GenevaWeed Research Laboratory, Nanjing Agricultural UniversityResearch Unit Environmental Science and Management, North-West University (Potchefstroom Campus)
  • , GovindjeeAffiliated withDepartment of Biochemistry, Department of Plant Biology, and Center of Biophysics & Computational Biology, University of Illinois at Urbana-Champaign Email author 

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This review is dedicated to David Walker (1928–2012), a pioneer in the field of photosynthesis and chlorophyll fluorescence. We begin this review by presenting the history of light emission studies, from the ancient times. Light emission from plants is of several kinds: prompt fluorescence (PF), delayed fluorescence (DF), thermoluminescence, and phosphorescence. In this article, we focus on PF and DF. Chlorophyll a fluorescence measurements have been used for more than 80 years to study photosynthesis, particularly photosystem II (PSII) since 1961. This technique has become a regular trusted probe in agricultural and biological research. Many measured and calculated parameters are good biomarkers or indicators of plant tolerance to different abiotic and biotic stressors. This would never have been possible without the rapid development of new fluorometers. To date, most of these instruments are based mainly on two different operational principles for measuring variable chlorophyll a fluorescence: (1) a PF signal produced following a pulse-amplitude-modulated excitation and (2) a PF signal emitted during a strong continuous actinic excitation. In addition to fluorometers, other instruments have been developed to measure additional signals, such as DF, originating from PSII, and light-induced absorbance changes due to the photooxidation of P700, from PSI, measured as the absorption decrease (photobleaching) at about 705 nm, or increase at 820 nm. In this review, the technical and theoretical basis of newly developed instruments, allowing for simultaneous measurement of the PF and the DF as well as other parameters is discussed. Special emphasis has been given to a description of comparative measurements on PF and DF. However, DF has been discussed in greater details, since it is much less used and less known than PF, but has a great potential to provide useful qualitative new information on the back reactions of PSII electron transfer. A review concerning the history of fluorometers is also presented.


Delayed fluorescence Fluorometers Photosystem II Prompt fluorescence