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Standard Fluorometer FL 6000-S

The core of the Standard Fluorometer FL 6000-S is the measuring optical head containing a standard cuvette for sample suspensions (10 x 10 mm base, up to 4 ml of internal volume). The measuring head is supplied with three sets of light-emitting diodes and a PIN diode detector with 500 kHz/16-bit AD converter. Gain and integration time of the converter are software controlled. The detector can measure Chl-fluorescence signal with time resolution up to 4 µs. Minimum detection limit is 100 ng Chla/l. Maximum detection limit depends on used protocol, it is approximatelly 26 mg Chla/l.

The Fluorometer is supplied with three, optionally four, sets of light-emitting diodes that generate:
  • Measuring flashes, typically 2-5 µs long. Standard color: red-orange, λmax=617 nm and blue, λmax=455 nm.
  • Single-turnover saturating flashes, typically 20-50 µs long. Standard color: red, λmax=630 nm (optionally blue λmax=455 nm; just one color possible for single-turnover saturating flashes).
  • Continuous actinic light. The maximum intensity is 3,000 µmol(photons).m-2.s-1. Standard color: red, λmax=630 nm (optionally blue λmax=455 nm; just one color possible for continuous actinic light).
  • Additional far-red lightmax=735 nm) for Photosystem I excitation (optional).

Fluorometer FL 3500 Light Scheme / Spectral CharacteristicsFluorometer FL 3500 Light Scheme / Spectral Characteristics
Fluorometer FL 6000 Light Scheme / Spectral Characteristics

Light intensities and timing are software controlled separately for each LED set. The data are processed and the instrument is controlled by the FluorWin software. As an option, the customer can also choose light-emitting diodes of different wavelengths. Contact PSI for your specific needs.

  • Four sets of light-emitting diodes – measuring light blue, measuring light red, single-turnover saturating light red, actinic light red
  • Light intensities and timings are software controlled separately for each LED set with 100 ns resolution
  • PIN photodiode detector with 40x variable gain for signal acquisition with 1MHz/16-bit maximum accuracy
  • The instrument capacity can be enhanced by accurate temperature regulation provided by the PSI Thermoregulator and Magnetic Stirrer Thermoregulator Magnetic Stirrer
    Thermoregulator / Magnetic Stirrer
  • Probing physiology of aquatic photoautotrophs
  • Measurement of efficiency of PSII photochemistry
  • Estimation of aquatic primary productivity
  • Molecular biology – screening for photosynthetic mutants
  • Detection of abiotic and biotic stress and stress tolerance
  • Taxonomical studies
  • Aquatic bloom detection
  • FL 6000
  • FL 6000
  • Chloroplasts & thylakoids
  • Algae & cyanobacteria
  • Small leaves or leaf segments
  • Sample Cuvette
  • Fluorescence induction
  • Pulse amplitude modulation measurements (PAM)
  • Fast OJIP transient capture
  • Rapid measurements of QA-reoxidation kinetics
  • State transitions
  • Quenching parameters
  • Photochemical yields
  • Fluorometer
  • Creation and archivation of experimental protocols
  • FluorWin Wizard for automated protocols
  • Retrieval and export of experimental data
  • Data manipulation and visualization
  • FluorWin Software: Wizard / Graph WindowFluorWin Software: Wizard / Graph Window
    FluorWin Software: Wizard / Graph Window
  • Measured Fluorescence Parameters:
    F0, FM, FV, F’0, F’M, F’V, FT
  • Light Sources:
    620 nm and 460 nm in standard versions; other wavelengths available as an option
  • Super Pulse Irradiance:
    80,000 µmol(photon).m-2.s-1 - adjustable from 0 to maximum
  • Actinic Light Irradiance:
    Up to 3,000 µmol(photon).m-2.s-1
  • Custom Defined Protocols:
    Variable timing, special language and scripts
  • A/D Bit Resolution:
    16 bit
  • Detector time response:
    1 µs in FL 6000-F
    4 µs in FL 6000-S
  • Communication Port:
    USB 2.0
  • Weight:
    5 kg
  • Dimensions:
    36 x 27 x 15 cm (Control Unit)
    Diameter 16 cm, height 6 cm (SuperHead Measuring Unit)
  • Power Input:
    20 W
  • Electrical:
    90 - 240 V
  • Warranty:
    1 year parts and labor
  • GRAMA B. S., AGATHOS S. N. AND JEFFRYES C. S. (2016): Balancing Photosynthesis and Respiration Increases Microalgal Biomass Productivity during Photoheterotrophy on Glycerol. ACS Sustainable Chem. Eng. Volume 4. Pages 1611–1618. DOI: 10.1021/acssuschemeng.5b01544
  • KOBAYASHI K., ENDO K. AND WADA H. (2016): Multiple Impacts of Loss of Plastidic Phosphatidylglycerol Biosynthesis on Photosynthesisduring Seedling Growth of Arabidopsis. Frontiers of Plant Sciences. Volume 7. DOI: 10.3389/fpls.2016.00336
  • CHEREGI O., KOTABOVÁ E., PRÁŠIL O., ET AL. (2015): Presence of state transitions in the cryptophyte alga Guillardia theta . Journal of Experimental Botany. Volume 66 . Pages 6461–6470. DOI: 10.1093/jxb/erv362
  • LI, G., BROWN, C. M., JEANS, J. A., ET AL. (2015): The nitrogen costs of photosynthesis in a diatom under current and future pCO2. New Phytologist. Volume 205. Pages 533–543. DOI:10.1111/nph.13037
  • NEGI S., BARRY A. N., FRIEDLAND N., ET AL. (2015): Impact of Nitrogen Limitation on Biomass, Photosynthesis, and Lipid Accumulation in Chlorella Sorokiniana. Journal of Applied Phycology. DOI 10.1007/s10811-015-0652-z
  • YOU L., HE L. AND TANG Y. J. (2015): Photoheterotrophic fluxome in Synechocystissp. strain PCC 6803 and its implications for cyanobacterial bioenergetics. Journal of bacteriol Bacteriology. Volume 197. Pages 943–950. DOI:10.1128/JB.02149-14
  • ZORZ J. K., ALLANACH J. R., MURPHY C. D., ET AL. (2015): The RUBISCO to Photosystem II Ratio Limits the Maximum Photosynthetic Rate in Picocyanobacteria. Life. Volume 5. Pages 403–417. DOI: 10.3390/life5010403
  • CHIŞ C., CHIŞ I., SICORA O., ET AL. (2014): Forward elektron transport measured in situ in microbibial mats from a hot spring in N-W Romania. Studia Universitatis Babes-Bolyai, Biologia. Volume 59. Pages 17-26.
  • KÁŇA R., KOTABOVA E., LUKEŠ M., ET AL. (2014): Phycobilisome Mobility and Its Role in the Regulation of Light Harvesting in Red Algae. Plant Physiology. Volume 165. Pages 1618–1631. DOI: 10.1104/pp.114.236075
  • KOTABOVÁ, E., JAREŠOVÁ, J., KÁŇA, R., ET AL. (2014): Novel type of red-shifted chlorophyll a antenna complex from Chromera velia. I. Physiological relevance and functional connection to photosystems. Biochimica et Biophysica Acta – Bioenergetics. Volume 1837. Pages 734-743. DOI: 10.1016/j.bbabio.2014.01.012
  • SOLHAUG K. A., XIE L. AND GAUSLAA Y. (2014): Unequal allocation of excitation energy between photosystem II and I reduces cyanolichen photosynthesis in blue light. Plant Cell Physiol. Volume 55. Pages 1404-14. DOI: 10.1093/pcp/pcu065
  • PETROU, K., TRIMBORN, S., ROST, B., ET AL. (2014): The impact of iron limitation on the physiology of the Antarctic diatom Chaetoceros simplex. Marine Biology. Volume 161. Pages 925-937. DOI: 10.1007/s00227-014-2392-z
  • BELATIK A., HOTCHANDANI S. AND CARPENTIER R. (2013): Inhibition of the water oxidizing complex of Photosystem II and the reoxidation of the quinone acceptor QA− by Pb2+. PLOS ONE. Volume 8. DOI: 10.1371/journal.pone.0068142
  • FRASER J.M., TULK S.E., JEANS J.A., ET AL. (2013): Photophysiological and Photosynthetic Complex Changes During Iron Starvation in Synechocystis sp. PCC 6803 and Synechococcus elongatus PCC 7942. PLoS ONE . Volume 8. DOI:10.1371/journal.pone.0059861
  • KRUPNIK T., KOTABOVA E., VAN BEZOUWEN L. S., ET AL. (2013): A reaction centre-dependent photoprotection mechanism in a highly robust photosystem II from an merolae extremophilic red alga Cyanidioschyzon. Journal of Biological Chemistry. Volume 288. Pages 23529–23542. DOI: 10.1074/jbc.M113.484659
  • SUMMERFIELD T. C., CRAWFORD T. S., YOUNG, R., ET AL. (2013): Environmental pH Affects Photoautotrophic Growth of Synechocystis sp. PCC 6803 Strains Carrying Mutations in the Lumenal Proteins of PSII. Plant &Cell Physiology. Volume 54. Pages 859–874. DOI: 10.1093/pcp/pct036
  • THOMAS S. AND CAMPBELL D. A. (2013): Photophysiology of Bolidomonas pacifica. Journal of Plankton Research. DOI: 10.1093/plankt/fbs105
  • VASS I. Z., KÓS P. B., SASS L., ET AL. (2013): The Ability of Cyanobacterial Cells to Restore UV-B Radiation Induced Damage to Photosystem II is Influenced by Photolyase Dependent DNA Repair. Photochem Photobiol. Volume 89. Pages 384–390. DOI: 10.1111/php.12012
  • VOLGUSHEVA A., STYRING S., MAMEDOV F. (2013): Increased photosystem II stability promotes H2 production in sulfur-deprived Chlamydomonas reinhardtii. Proceedings of the National Academy of Sciences of the United States of America. Volume 110. Pages7223-7228. DOI:10.1073/pnas.1220645110
  • KÁŇA R., KOTABOVA E., SOBOTKA R., ET AL. (2012): Non-Photochemical quenching in Cryptophyte Alga Rhodomonas salina is located in chlorophyll a/c antennae. PLOS ONE . Volume 7. DOI: 10.1371/journal.pone.0029700
  • KATO Y., SHIBAMOTO T., YAMAMOTO S., ET AL. (2012): Influence of the PsbA1/PsbA3, Ca2+/Sr2+ and Cl−/Br− exchanges on the redox potential of the primary quinone QA in Photosystem II from Thermosynechococcus elongatus as revealed by spectroelectrochemistry. Biochimica et Biophysica Acta (BBA) – Bioenergetics. Volume 1817. Pages 1998-2004. DOI: 10.1016/j.bbabio.2012.06.006
  • KVÍDEROVÁ J.(2012): Photochemical performance of the acidophilic red alga Cyanidium sp. in a pH gradient. Orig. Life Evol. Bios. Volume 42. Pages 223-234. DOI: 10.1007/s11084-012-9284-3
  • PERRINE Z., NEGI S., SAYRE R. T. (2012): Optimization of photosynthetic light energy utilization by microalgae, Algal Research, Volume 1. Pages 134-142. DOI: 10.1016/j.algal.2012.07.002
  • QUIGG A., KOTÁBOVÁ E., JAREŠOVÁ J., ET AL. (2012): Photosynthesis in Chromera velia represents a simple system with high efficiency. PLOS ONE. Volume 7. DOI:10.1371/journal.pone.0047036
  • WANG S. AND PAN X. (2012): Effects of Sb(V) on growth and chlorophyll fluorescence of Microcystis aeruginosa (FACHB-905). Current Microbiology. Volume 65. Pages 733 - 741. DOI: 10.1007/s00284-012-0221-5
  • WANG S., ZHANG D., PAN X. (2012): Effects of arsenic on growth and photosystem II (PSII) activity of Microcystis aeruginosa, Ecotoxicology and Environmental Safety, Volume 84. Pages 104-111. DOI: 10.1016/j.ecoenv.2012.06.028
  • ALLAKHVERDIEV S. I., TSUCHIYA T., WATABE K., ET AL. (2011): Redox potentials of primary electron acceptor quinone molecule (QA)− and conserved energetics of photosystem II in cyanobacteria with chlorophyll a and chlorophyll d. PNAS. Volume 108. Pages 8054-8058. DOI:10.1073/pnas.1100173108
  • HAKALA-YATKIN M. AND TYYSTJARVI E. (2011): Inhibition of Photosystem II by the singlet oxygen sensor compounds TEMP and TEMPD. Biochimica et Biophysica Acta. Volume 1807. Pages 243-250. DOI:10.1016/j.bbabio.2010.11.014
  • JEANTHON C., BOEUF D., DAHAN O., ET AL. (2011): Diversity of cultivated and metabolically active aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea. Biogeosciences. Volume 8. Pages 1955-1970. DOI:10.5194/bg-8-1955-2011
  • RANTAMAKI S. AND TYYSTJARVI E. (2011): Analysis of S2 QA- charge recombination with the Arrhenius, Eyring and Marcus theories. J. Photochem. Photobiol. B 104. Pages 292-300. DOI:10.1016/j.jphotobiol.2011.03.013
  • KVÍDEROVÁ J. (2010): Rapid algal toxicity assay using variable chlorophyll fluorescence for Chlorella kesslerii (Chlorophyta). Environ. Toxicol. Volume 25. Pages 554-563. DOI: 10.1002/tox.20516
  • KVÍDEROVÁ J. (2010): Characterization of the community of snow algae and their photochemical performance in situ in the Giant Mountains, Czech Republic. AAAR . Volume 42. Pages 210-218. DOI: 10.1657/1938-4246-42.2.210
  • SHIBAMOTO T., KATO Y., NAGAO R., ET AL.(2010): Species-dependence of the redox potential of the primary quinone electron acceptor QA in photosystem II verified by spectroelectrochemistry. FEBS Letters. Volume 584. DOI: 10.1016/j.febslet.2010.03.002
  • PAN X., CHEN X., ZHANG D., ET AL. (2009): Effect of chromium (VI) on Photosystem II activity and heterogeneity of Synechocystis sp. (Cyanophyta): studied with in vivo chlorophyll fluorescence tests. J. Phycol. Volume 45. Pages 386–394. DOI: 10.1111/j.1529-8817.2009.00647.x
  • POLLARI M., RUOTSALAINEN V., RANTAMAKI S., ET AL.(2009): Simultaneous inactivation of sigma factors B and D interferes with light acclimation of the cyanobacterium Synechocystis sp. strain PCC 6803. Journal of Bacteriology. Volume 191.Pages 3992-4001. DOI: 10.1128/JB.00132-09
  • THAPPER A., MAMEDOV F., MOKVIST F., ET AL. (2009): Defining the Far-Red Limit of Photosystem II in Spinach. Plant Cell. Volume 2. Pages 2391–2401. DOI: 10.1105/tpc.108.064154
  • ALLAHVERDIYEVA Y., MAMEDOV F., SUORSA M., ET AL. (2007): Insights into the function of PsbR protein in Arabidopsis thaliana. BBA. Volume 1767. Pages 677-685. DOI:10.1016/j.bbabio.2007.01.011
  • MAMEDOV F., NOWACZYK M. M., THAPPER A., ET AL. (2007): Functional Characterization of Monomeric Photosystem II Core Preparations from Thermosynechococcus elongatus with or without the Psb27 Protein. Biochemistry. Volume 46. Pages 5542-5551. DOI: 10.1021/bi7000399
  • CEPÁK V., PŘIBYL P., KVÍDEROVÁ J., ET AL. (2006): Comparative study of zooid and non-zooid forming strains of Scenedesmus obliquus. Physiology and Cytomorphology. Folia Microbiologica, Volume 51. Pages 250-259. DOI: 10.1007/BF02931829
  • LAZÁR D. (2006): The polyphasic chlorophyll a fluorescence rise measured under high intensity of exciting light. Functional Plant Biology. Volume 33. Pages 9-30. DOI: 10.1071/FP05095
  • SHLYK-KERNER O., SAMISH I., KAFTAN D., ET AL. (2006): Protein flexibility acclimatizes photosynthetic energy conversion to the ambient temperature. Nature. Volume 442. Pages 827-830. DOI:10.1038/nature04947
  • VACZI P. AND BARTÁK M. (2006): Photosynthesis of lichen symbiotic alga Trebouxia erici as affected by irradiance and osmotic stress. Biol. Plant. Volume 50. Pages 257-264. DOI: 10.1007/s10535-006-0016-2
  • ALLAHVERDIYEVA Y., MAMEDOV F., MAENPAA P., ET AL.(2005): Modulation of photosynthetic electron transport in the absence of terminal electron acceptors: Characterization of the rbcL deletion mutant of tobacco. BBA 1709. Pages 69-83. DOI:10.1016/j.bbabio.2005.06.004
  • KVÍDEROVÁ J., STÍBAL M., NEDBALOVÁ L., ET AL. (2005): The first record of snow algae vitality in situ by variable fluorescence of chlorophyll. Czech Phycol. Volume 5. Pages 69-77.
  • NEDBAL L., BŘEZINA V., ČERVENÝ J., ET AL. (2005): Photosynthesis in dynamic light: Systems biology of unconventional chlorophyll fluorescence transients in Synechocystis sp.PCC6803. Photosynth. Res. Volume 84. Pages 99-106. DOI: 10.1007/s11120-004-6428-y
  • MOCK T. AND VALENTIN K. (2004): Photosynthesis and cold acclimation: Molecular evidence from a polar diatom. J. Phycol. Volume 40. Pages 732-741. DOI: 10.1111/j.1529-8817.2004.03224.x
  • SIGFRIDSSON K. G. V., BERNAT G., MAMEDOV F., ET AL. (2004): Molecular interference of Cd2+ with Photosystem II. BBA Volume 1659. Pages 19-31. DOI:10.1016/j.bbabio.2004.07.003
  • MOCK T. AND KROON B. M. A. (2002): Photosynthetic energy conversion under extreme conditions: Important role of lipids as structural modulators and energy sink under N-limited growth in Antarctic sea ice diatoms. Phytochemistry. Volume 61. Pages 41-51. DOI: 10.1016/S0031-9422(02)00216-9
  • KOBLÍŽEK M., KAFTAN D. AND NEDBAL L. (2001): On the relationship between the non-photochemical quenching of the chlorophyll fluorescence and the Photosystem II light harvesting efficiency. A repetitive flash fluorescence induction study. Photosynthesis Research. Volume 68. Pages 141-152. DOI: 10.1023/A:1011830015167
  • SKOTNICA J., MATOUŠKOVÁ M., NAUŠ J., ET AL. (2000) Thermoluminescence and fluorescence study of changes in Photosystem II photochemistry in desiccating barley leaves. Photosynthesis Research. Volume 65. Pages 29-40. DOI: 10.1023/A:1006472129684
  • NEDBAL L., TRTÍLEK M., AND KAFTAN D. (1999): Flash fluorescence induction: a novel method to study regulation of Photosystem II. J. Photochem. Photobiol., Volume 48. Pages 154-157.
  • TRTÍLEK M., KRAMER D. M., KOBLÍŽEK M., ET AL. (1997): Dual-modulation LED kinetic fluorometer. Journal of Luminescence, Volumes 72–74, June 1997, Pages 597-599, DOI: 10.1016/S0022-2313(97)00066-5


  • Orders and Payments
  • Standard Fluorometer FL 6000-S
    8.490,- €
  • Infra-Red LED Unit
    1.490,- €
  • Thermoregulator TR 2000
    2.999,- €
  • Magnetic Stirrer
    998,- €
  • PC with Preinstalled Control Software *
    390,- €
  • Oxygen Detector Module
    1.550,- €
  • Oxygen Electrode *
    690,- €
  • Additional SuperHead
    3.490,- €

Optional Features and Accessories

Thermoregulator TR 2000
Provides precise temperature control in the range of 0 °C to +70 °C with an accuracy of 0.1 °C. The actual temperature is displayed on the front panel of the device. It includes control unit and temperature controller. TR 2000 can work in two modes: (i) constant mode, (ii) temperature ramp mode. In the constant mode, the instrument maintains a constant temperature of the measured sample. The temperature ramp mode enables linear changing of the sample temperature with a rate ranging from 0.1 °C/sec to 1 °C/sec.

Magnetic Stirrer
Magnetic Stirrer is designed to provide continuous stirring with little speed deviation and minimum heat build-up. Continuous, uniform stirring is essential for keeping a constant temperature within the entire sample volume when the temperature control is applied. The rate of stirring is set by a knob on the front panel of the device. Magnetic Stirrer is a handy accessory to PSI Fluorometers: it can be connected to the Fluorometer Control Unit and controlled by it (switched on and off). Two stirring bars are included in the price.

Oxygen Detector
Serves for oxygen evolution detection based on dynamic quenching of fluorescence (electrode sold separately). Important notice: Mechanical construction of the fluorometer does not allow simultaneous measurement of fluorescence and oxygen evolution.
NOTE: It is highly recommended to use the oxygen detector module with the Magnetic Stirrer.

Oxygen Electrode *
Supplement to oxygen detector module.

Infra-Red LED Unit
Allows measuring Fo' and PAR absorbance. It is also used during quenching analysis protocol.

PC with Preinstalled Control Software *
Notebook PC with preinstalled software for fluorometer control.

Additional SuperHead
Fluorometer standard configuration can be enhanced by adding a second SuperHead. This SuperHead can be constructed with respect to customer's experimental needs: specific LED colors, which cannot be added to the first SuperHead (Blue, Cyan, Amber) and detection bands (ChlA, ChlB).


FluorWin 3.6
OS: Win2000/XP/Win7 (32bit)/Win8 (32 bit)
Language: English
Size: 1.6 MB

FluorWin 3.7 (for FM 3500/F)
OS: Win2000/XP/Win7 (32bit)/Win8 (32 bit)/Win10 (64) compatible
Language: English
Size: 1.6 MB

FluorWin 3.7 standard (for FM 3500/S)
OS: Win2000/XP/Win7 (32bit)/Win8 (32 bit)/Win10 (64) compatible
Language: English
Size: 1.6 MB

Fluorometer Manual
Type: PDF
Language: English
Size: 4.8 MB

Magnetic Stirrer User Guide
Type: PDF
Language: English

Thermoregulator TR 2000 Manual
Type: PDF
Language: English
Size: 754 KB

Algal Online Monitor Operation Manual
Type: PDF
Language: English
Size: 1.9 MB

FL3500 - Overview of Single Models
Type: PDF
Language: English
Size: 360 KB

Other Fluorometers

Standard Fluorometer FL 3500-S

Highly compact:
Measuring optical head with a standard cuvette for sample suspensions of aquatic or terrestrial plants.

Typical samples:
Suspensions of photosynthetically active organisms, small leaves, or leaf segments.

Fast Fluorometer FL 3500-F

Supported investigations:
- PAM measurements
- Fast kinetic measurements of OJIP
- Flash fluorescence induction
- State transitions etc.

Time resolution of 1 µs.

Algal Online Monitor

Flow-through monitoring:
Enables detection and continuous quantifying of photosynthetically active microorganisms in rivers, lakes, or artificial water reservoirs.

Detection limit: 30 ng Chl/l.

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