Skip to main content

Abstract

Chlorophyll fluorescence (CF) is red and far-red light that is emitted from photosynthetic green plant tissues in response to photosynthetically active radiation. Although the total amount of CF is very small (typically less than 5% of total light absorbed), it is easily quantified with sensitive instrumentation. CF may be analyzed using plants that have been dark-adapted to provide Kautsky induction features (Kautsky and Hirsch, 1931), or under steady-state light (see introductory chapter). When a dark-incubated leaf is suddenly exposed to light, CF emission initially spikes then gradually subsides to a steady-state level within a few minutes. This pattern can provide direct and indirect information about photosynthetic function, and in particular about the efficiency and status of photosystem II (PSII), which with photosystem I (PSI) is responsible for the early events in photosynthesis (Dreyer, 1997). Some contribution to CF comes from PSI at wavelengths greater than 700 nm (30% up to 50% in C3 and C4 plants, respectively), but PSI does not contribute to the variable component of CF, that is, the fluorescence above the O-level (Pfundel, 1998; Dreyer, 1997).

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 84.99
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 109.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 109.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  • Adams, W.W. III, and B. Demmig-Adams. 1994. Carotenoid composition and down regulation of photosystem II in three conifer species during the winter. Physiol. Plant. 92:451–458.

    Article  CAS  Google Scholar 

  • Adams, W.W. III, B. Demmig-Adams, K. Winter, and U. Schreiber. 1990. [A] The ratio of variable to maximum chlorophyll fluorescence from photosystem II, measured in leaves at ambient temperature and at 77 K, as an indicator of the photon yield of photosynthesis. Planta 180:166–174.

    Article  CAS  Google Scholar 

  • Adams, G.T., and T.D. Perkins. 1993. Assessing cold tolerance in Picea using chlorophyll fluorescence. Environ. Expt. Bot. 33:377–382.

    Article  CAS  Google Scholar 

  • Adams, W.W. III, K. Winter, U. Schreiber, and P. Schramel. 1990. [B] Photosynthesis and chlorophyll fluorescence characteristics in relationship to changes in pigment and element composition of leaves of Platanus occidentalis L. during autumnal leaf senescence. Plant Physiol. 92:1184–1190.

    Article  PubMed  CAS  Google Scholar 

  • Agati, G., P. Mazzinghi, F. Fusi, and I. Ambrosini. 1995.The F685/F730 chlorophyll fluorescence ratio as a tool in plant physiology: Response to physiological and environmental factors. J. Plant Physiol. 145:228–238.

    Article  CAS  Google Scholar 

  • Baillon, F., X. Dalschaert, S. Grassi, and F. Geiss. 1988. Spruce photosynthesis: possibility of early damage diagnosis due to exposure to magnesium or potassium deficiency. Trees 2:173–179.

    Article  Google Scholar 

  • Bail, M.C., J.A. Butterworth, J.S. Roden, R. Christian, and J.J.G. Egerton. 1995. Applications of chlorophyll fluorescence to forest ecology. Aust. J. Plant Physiol. 22:311–319.

    Article  Google Scholar 

  • Barnes, J.D., and A.W. Davison. 1988. The influence of ozone on the winer hardiness of Norway spruce (Picea abies (L.) Karst.). New Phytol. 108:159–166.

    Article  CAS  Google Scholar 

  • Barnes, J.D., T. Pfirrmann, K. Steiner, C. Lutz, U. Busch, H. Kuchenhoff, and H.D. Payer. 1995. Effects of elevated CO2, elevated O3 and potassium deficiency on Norway spruce (Picea abies (L.) Karst.): seasonal changes in photosynthesis and non-structural carbohydrate content. Plant Cell Environ. 18:1345–1357.

    Article  CAS  Google Scholar 

  • Bartak, M., A. Raschi, and R. Tognetti. 1999. Photosynthetic characteristics of sun and shade leaves in the canopy of Arbutus unedo L. trees exposed to in situ long-term elevated CO2. Photosynthetica 37:l-16.

    Article  Google Scholar 

  • Bauer, H., M. Nagele, M. Comploj, V. Galler, M. Mair, and E. Unterpertinger. 1994. Photosynthesis in cold acclimated leaves of plants with various degrees of freezing tolerance. Physiol. Plant. 91:403–412.

    Article  CAS  Google Scholar 

  • Bauer, H., K. Plattner, and W. Volgger. 2000. Photosynthesis in Norway spruce seedlings infected by the needle rust Chrysomyxa rhododendri. Tree Physiol. 20:211–216.

    Article  PubMed  CAS  Google Scholar 

  • Bavcon, J., A. Gagerscik, and F. Batic. 1996. Influence of UV-B radiation on photosynthetic activity and chlorophyll fluorescence kinetics in Norway spruce (Picea abies (L.) Karst.) seedlings. Trees 10:172–176.

    Google Scholar 

  • Bergh, J., and S. Linder. 1999. Effects of soil warming during spring on photosynthetic recovery in boreal Norway spruce stands. Global Change Biol. 5:245–253.

    Article  Google Scholar 

  • Bilger, W., and O. Bjorkman. 1990.Role of the xanthophyll cycle in photoprotection elucidated by measurements of light-induced absorbance changes, fluorescence and photosynthesis in Hedera canariensis. Photosynth. Res. 25:173–185.

    CAS  Google Scholar 

  • Bilger, W., U. Schreiber, and M. Bock. 1995. Determination of the quantum efficiency of photosystem Il and of non-photochemical quenching of chlorophyll fluorescence in the field. Oecologia 102:425–432.

    Article  Google Scholar 

  • Binder, W.D., and P. Fielder. 1996a. Chlorophyll fluorescence as an indicator of frost hardiness in white spruce seedlings from different latitudes. New For. 11:233–253.

    Google Scholar 

  • Binder, W.D., and P. Fielder. 1996b. Seasonal changes in chlorophyll fluorescence of white spruce seedlings from different latitudes in relation to gas exchange and winter storability. New For. 11:207–232.

    Google Scholar 

  • Bjorkman, O., and B. Demmig. 1987. Photon yield of O2 evolution and chlorophyll fluorescence characteristics at 77 K among vascular plants of diverse origins. Planta 170:489–504.

    Article  Google Scholar 

  • Blennow, K., A.R.G. Lang, P. Dunne, and M.C. Ball. 1998. Cold-induced photoinhibition and growth of seedling snow gum (Eucalyptus pauciflora) under differing temperature and radiation regimes in fragmented forests. Plant Cell Environ. 21:407–416.

    Article  Google Scholar 

  • Bolhar-Nordenkampf, H.R., and E.G. Lechner. 1988. Temperature and light dependent modifications of chlorophyll fluorescence kinetics in spruce needles during winter. Photosynth. Res. 18:287–298.

    Article  CAS  Google Scholar 

  • Bolhar-Nordenkampf, H.R., S.P. Long, N.R. Baker, G. Oquist, U. Schreiber, and E.G. Lechner. 1989. Chlorophyll fluorescence as a probe of the photosynthetic competence of leaves in the field: A review of current instrumentation. Funct. Ecol. 3:497–514.

    Article  Google Scholar 

  • Brodribb, T., and R.S. Hill. 1997. Light response characteristics of a morphologically diverse group of southern hemisphere conifers as measured by chlorophyll fluorescence. Oecologia 110:10–17.

    Article  Google Scholar 

  • Burr, K.E., C.D.B. Hawkins, S.J. L’Hirondelle, W.D. Binder, M.F. George, and T. Repo. 2000. Methods for measuring cold hardiness of conifers, p. 369–401. In: F.J. Bigras and S.J. Colombo (eds.), Conifer Cold Hardiness. Kluwer Academic, Dordrecht.

    Google Scholar 

  • Calatayud, A., V.I. Deltoro, A. Abadia, J. Abadia, and E. Barreno. 1999. Effects of ascorbate feeding on chlorophyll fluorescence and xanthophyll cycle components in the lichen Parmelia quercina (Willd.) Vainio exposed to atmospheric pollutants. Physiol. Plant. 105:679–684.

    Article  CAS  Google Scholar 

  • Camm, E.L., R.D. Guy, D.S. Kubien, D.C. Goetze, S.N. Silim, and P.J. Burton. 1995. Physiological recovery of freezer-stored white and Engelmann spruce seedlings planted following different thawing regimes. New For. 10:55–77.

    Google Scholar 

  • Carter, G.A., J.H. Jones, R.J. Mitchell, and C.H. Brewer. 1996. Detection of solar-excited chlorophyll a fluorescence and leaf photosynthetic capacity using a Fraunhofer line radiometer. Remote Sensing Environ. 55:89–92.

    Article  Google Scholar 

  • Carter, G.A., A.F. Theisen, and R.J. Mitchell. 1990. Chlorophyll fluorescence measured using the Fraunhofer line-depth principle and relationship to photosynthetic rate in the field. Plant Cell Environ. 13:79–83.

    Article  CAS  Google Scholar 

  • Castro, Y., Fetcher N., and D.S. Fernandez. 1995. Chronic photoinhibition in seedlings of tropical trees. Physiol. Plant. 94:560–565.

    Article  CAS  Google Scholar 

  • Cerovic, Z.G., Y. Goulas, M. Gorbunov, J.M. Briantais, L. Camenen, and I. Moya. 1996. Fluorosensing of water stress in plants: Diurnal changes of the mean lifetime and yield of chlorophyll fluorescence, measured simultaneously and at distance with a t-LlDAR and a modified PAM-fluorimeter, in maize, sugar beet, and kalanchoe. Remote Sensing Environ. 58:311–321.

    Article  Google Scholar 

  • Cerovic, Z.G., G. Samson, F. Morales, N. Tremblay, and I. Moya. 1999. Ultraviolet-induced fluorescence for plant monitoring: present state and prospects. Agronomie 19:543–578.

    Article  Google Scholar 

  • Chappelle, E.W., and D.L. Williams. 1995. Laser-induced fluorescence (LIF) from plant foliage. IEEE Trans Geoscience Remote Sensing 1987, GE-25. 6:726–736.

    Google Scholar 

  • Chekalyuk, A.M., and M.Y. Gorbunov. 1995. New capabilities of laser remote sensing for measurement of photosynthetic parameters of phytoplankton and higher plants, p. 37–43. In: Proc. Intl. Colloq. Photosynth. Remote Sensing, EARSel, Avignon, INRA, France.

    Google Scholar 

  • Clark, A.J., W. Landolt, J.B. Bucher, and R.J. Strasser. 2000. Beech (Fagus sylvatica) response to ozone exposure assessed with a chlorophyll a fluorescence performance index. Environ. Pollut. 109:501–507.

    Article  PubMed  CAS  Google Scholar 

  • Damesin, C.,, and S. Rambal. 1995. Field study of leaf photosynthetic performance by a Mediterranean deciduous oak tree (Quercus pubescens) during a severe summer drought. New Phytol. 131:159–167.

    Article  Google Scholar 

  • Dreyer, E. 1997. Photosynthesis and drought in forest trees, p. 215–238. In: H. Rennenberg, W. Eschrich, and H. Ziegler (eds.), Trees - Contributions to Modern Tree Physiology. Backhuys Publishers, Leiden, The Netherlands.

    Google Scholar 

  • Dreyer, E., D. Epron, and O.E.Y. Matig. 1992. Photochemical efficiency of photosystem II in rapidly dehydrating leaves of 11 temperate and tropical tree species differing in their tolerance to drought. Ann. Sci. For. 49:615–625.

    Article  Google Scholar 

  • Edner, H., J. Johansson, S. Svanberg, and E. Wallinder. 1994. Fluorescence lidar multicolor imaging of vegetation. Appl. Optics 33:2471–2479.

    Article  CAS  Google Scholar 

  • Egerton, J.J.G., J.C.G. Banks, A. Gibson, R.B. Cunningham, and M.C. Ball. 2000. Facilitation of seedling establishment: reduction in irradiance enhances winter growth of Eucalyptus pauciflora. Ecol. 81:1437–1449.

    Google Scholar 

  • Evans, E.H., R.G. Brown, and A.R. Wellburn. 1992. Chlorophyll fluorescence decay profiles of O3-exposed spruce needles as measured by time-correlated single photon counting. New Phytol. 122:501–506.

    Article  CAS  Google Scholar 

  • Falls, R.W., P. Toivonen, and I.E.P. Taylor. 1991. Chlorophyll a fluorescence and preseason seedling dimensions as indicators of wood formation rates in white spruce (Picea glauca). Can. J. For. Res. 21:1106–1110.

    Article  Google Scholar 

  • Faria, T., J.I. Garcia-Plazaola, A. Abadia, S. Cerasoli, J.S. Pereira, and M.M. Chaves. 1996. Diurnal changes in photoprotective mechanisms in leaves of cork oak (Quercus suber) during summer. Tree Physiol. 16:115–123.

    Article  PubMed  Google Scholar 

  • Fleck, I., X. Aranda. B. El Omari, J. Permanyer, A. Abadia, and K.P. Hogan. 2000. Light energy dissipation in Quercus ilex resprouts after fire. Aust. J. Plant Physiol. 27:129–137.

    Google Scholar 

  • Fleck, I., K.P. Hogan, L. Llorens, A. Abadia, X. Aranda, and P.J. Dye. 1998. Photosynthesis and photoprotection in Quercus ilex resprouts after fire. Tree Physiol. 18:607–614.

    Article  PubMed  CAS  Google Scholar 

  • Flexas, J., J.-M. Briantais, Z. Cerovic, H. Medrano, and I. Moya. 2000. Steady-state and maximum chlorophyll fluorescence responses to water stress in grapevine leaves: a new remote sensing system. Remote Sensing Environ. 73:282–297.

    Article  Google Scholar 

  • Franco, A.C., A. Haag-Kerwer, B. Herzog, T.E.E. Grams, E. Ball, E.A. de Mattos, F.R. Scarano, S. Barreto, M.A. Garcia, A. Mantovani, and U. Luttge. 1996. The effect of light levels on daily patterns of chlorophyll fluorescence and organic acid accumulation in the tropical CAM tree Clusia hilariana. Trees 10:359–365.

    Google Scholar 

  • Garcia-Plazaola, J.I., T. Faria, J. Abadia, MM. Chaves, and J.S. Pereira. 1997. Seasonal changes in xanthophyll composition and photosynthesis of cork oak (Quercus suber L.) leaves under Mediterranean climate. J. Expt. Bot. 48:1667–1674.

    CAS  Google Scholar 

  • Gauslaa, Y., and K.A. Solhaug. 2000. High-light-intensity damage to the foliose lichen Lobaria pulmonaria within a natural forest: the applicability of chlorophyll fluorescence methods. Lichenologist 32:271–289.

    Article  Google Scholar 

  • Genty, B., J.-M. Briantais, and N.R.. Baker. 1989. The relationship between the quantum yield of photosynthetic electron transport and quenching of chlorophyll fluorescence. Biochim. Biophys. Acta 990:87–92.

    Article  CAS  Google Scholar 

  • Gillies, S.L. 1993.A physiological study of fall dormancy and spring reactivation of photosynthesis in seedlings of white spruce [Picea glauca (Moench) Voss] and Douglasfir [Pseudotsuga menziesii (Mirb.) Franco]. PhD thesis, Department of Biological Sciences; ISBN 0-315-91156-5, 192 pp. Simon Fraser University, Burnaby, British Columbia, Canada.

    Google Scholar 

  • Gillies, S.L., and W.E. Vidaver. 1993. Recovery of photosynthetic activity in conifer seedlings after cold storage. Plant Physiol. (suppl.) 102:138.

    Google Scholar 

  • Gitelson, A.A., C. Buschmann, and H.K. Lichtenthaler. 1999. The chlorophyll fluorescence ratio F735/F700 as an accurate measure of the chlorophyll content in plants. Remote Sensing Environ. 69:296–302.

    Article  Google Scholar 

  • Gitelson, A.A., and M.N. Merzlyak. 1996. Signature analysis of leaf reflectance spectra: algorithm development for remote sensing of chlorophyll. J. Plant Physiol. 148:494–500.

    Article  CAS  Google Scholar 

  • Godde, D., and J. Buchhold. 1992. Effect of long term fumigation with ozone in the turnover of the D-l reaction center polypeptide of photosystem II in spruce (Picea abies). Physiol. Plant. 86:568–574.

    Article  CAS  Google Scholar 

  • Govindjee. 1995. Sixty-three years since Kautsky: chlorophyll a fluorescence. Aust. J. Plant Physiol. 22:131–160.

    Article  CAS  Google Scholar 

  • Gunther, K.P., H.-G. Dahn, and W. Ludeker. 1994. Remote sensing vegetation status by laserinduced fluorescence. Remote Sensing Environ. 47:10–17.

    Article  Google Scholar 

  • Haitz, M., and H.K. Lichtenthaler. 1988. The measurement of Rfd values as plant vitality indices with the portable field chlorophyll fluorometer and the PAM-fluorometer, p. 249– 254. In: H.K. Lichtenthaler (ed.), Applications of Chlorophyll Fluorescence in Photosynthesis Research, Stress Physiology, Hydrobiology and Remote Sensing. Kluwer Academic, Dordrecht, The Netherlands.

    Chapter  Google Scholar 

  • Hak, R., H.K. Lichtenthaler, and U. Rinderle. 1990. Decrease of the chlorophyll fluorescence ratio F690/F730 during greening and development of leaves. Radiat. Environ. Biophys. 29:329–336.

    Article  PubMed  CAS  Google Scholar 

  • Hamerlynck, E., and A.K. Knapp. 1996. Photosynthetic and stomatal responses to high temperature and light in two oaks at the western limit of their range. Tree Physiol. 16:557–565.

    Article  PubMed  Google Scholar 

  • Harbinson, J., and F.I. Woodward. 1984. Field measurements of the gas exchange of woody plant species in simulated sunflecks. Ann. Bot. 53:841–851.

    Google Scholar 

  • Havaux, M., M. Ernez, and R. Lannoye. 1988.Tolerance of poplar (Populus sp) to environmental stresses. I. Comparative study of poplar clones using the in vivo chlorophyll fluorescence method. Acta Oecologia/Oecologia Plant. 9:161–172.

    Google Scholar 

  • Hawkins, C.D.B., and G.R. Lister. 1985. In vivo chlorophyll fluorescence as an indicator of the dormancy stage in Douglas fir seedlings. Can. J. For. Res. 15:607–612.

    Article  CAS  Google Scholar 

  • Hoddinott. J., and R. Scott. 1996. The influence of light quality and carbon dioxide enrichment on the growth and physiology of seedlings of three conifer species. II. Physiological responses. Can. J. Bot. 74:391–402.

    Article  Google Scholar 

  • Hoge. F.E., R.N. Swift, and I.K. Yungel. 1983. Feasibility of airborne detection of laserinduced fluorescence emission from green terrestrial plants. Appl. Optics 22:2991–3000.

    Article  CAS  Google Scholar 

  • Hoque, E., and G. Remus. 1994. Native and atrazine-induced fluorescence of chloroplasts from palisade and spongy parenchyma of beech (Fagus sylvatica L.) leaves. Remote Sensing Environ. 47:77–86.

    Article  Google Scholar 

  • Hymus, G.J., D.S. Ellsworth, N.R. Baker, and S.P. Long. 1999. Does free-air carbon dioxide enrichment affect photochemical energy use by evergreen trees in different seasons? A chlorophyll fluorescence study of mature loblolly pine. Plant Physiol. 120:1183–1191.

    Article  PubMed  CAS  Google Scholar 

  • Ishida, A., T. Nakano, Y. Matsumoto, ML Sakoda, and L.-H. Ang. 1999a. Diurnal changes in leaf gas exchange and chlorophyll fluorescence in tropical tree species with contrasting light requirements. Ecol. Res. 14:77–88.

    Article  Google Scholar 

  • Ishida, A., T. Toma, and Marjenah. 1999b. Leaf gas exchange and chlorophyll fluorescence in relation to leaf angle, azimuth, and canopy position in the tropical pioneer tree, Macaranga conifera. Tree Physiol. 19:117–124.

    Article  PubMed  Google Scholar 

  • Ishida, A., T. Toma, and Marjenah. 1999c. Limitation of leaf carbon gain by stomatal and photochemical processes in the top canopy of Macaranga conifera, a tropical pioneer tree. Tree Physiol. 19:467–473.

    Article  PubMed  CAS  Google Scholar 

  • Ishida, A., A. Uemura, N. Koike, Y. Matsumoto, and A.-L. Hoe. l999d. Interactive effects of leaf age and self-shading on leaf structure, photosynthetic capacity and chlorophyll fluorescence in the rain forest tree, Dryobalanops aromatica. Tree Physiol. 19:741–747.

    Article  PubMed  Google Scholar 

  • Johansson, J., M. Anderson, H. Edner, J. Mattsson, and S. Svanberg. 1996.Remote fluorescence measurements of vegetation spectrally resolved and by multi-colour fluorescence imaging. J. Plant Physiol. 148:632–637.

    Article  CAS  Google Scholar 

  • Johnson, J.D., and H.E. Stelzer. 1991. Loblolly pine photosynthesis is enhanced by sublethal hexazinone concentrations. Tree Physiol. 8:371–379.

    Article  CAS  Google Scholar 

  • Kalina, J., M.V. Marek, and V. Spunda. 1994. Combined effects of irradiance and first autumn frost on CO2 assimilation and selected parameters of chlorophyll a fluorescence in Norway spruce shoots. Photosynthetica 30:233–242.

    CAS  Google Scholar 

  • Karpinski, S., B. Karpinska, G. Wingsle, and J.E. Hallgren. 1994. Molecular responses to photooxidative stress in Pinus sylvestris. I. Differential expression of nuclear and plastid genes in relation to recovery from winter stress. Physiol. Plant. 90:358–366.

    Article  CAS  Google Scholar 

  • Kautsky,H., and A.Hirsch.1931. Neue versuche zur kohlensaureassimilation. Naturwissenschaften 19:964.

    Article  CAS  Google Scholar 

  • Kebabian, P.L., A. Freedman. S. Kallelis, and H.E. Scott. 1998. A passive two-band sensor for sunlight-excited plant fluorescence, p. I-21 - I–27. Proc. 1st Intl. Conf. Geospatial Information in Agriculture and Forestry. Lake Buena Vista, Florida.

    Google Scholar 

  • Kebabian, P.L., A.F. Theisen, S. Kallelis, and A. Freedman. 1999. A passive two-band sensor for sunlight-excited plant fluorescence. Rev. Sci. Instrum. 70:4386–4393.

    Article  CAS  Google Scholar 

  • Keiper, F.J., D.M. Chen, and L.F. de.Filippis. 1998.Respiratory, photosynthetic and ultrastructural changes accompanying salt adaptation in culture of Eucalyptus microcorys. J. Plant Physiol. 152:564–573.

    Article  CAS  Google Scholar 

  • Kellomaki, S., and K.-Y. Wang. 1997. Effects of elevated O3 and CO2 on chlorophyll fluorescence and gas exchange in Scots pine during the third growing season. Expt. Pollut. 97:17–27.

    Article  CAS  Google Scholar 

  • Kharuk, V.I., V.N. Morgun, B.N. Rock, and D.L. Williams. 1994. Chlorophyll fluorescence and delayed fluorescence as potential tools in remote sensing: A reflection of some aspects of problems in comparative analysis. Remote Sensing Environ. 47:98–105.

    Article  Google Scholar 

  • Kim, H.H. 1973. New algae mapping technique by use of an airborne laser fluorosensor. Appl. Optics 12:1454–1459.

    Article  CAS  Google Scholar 

  • Kitao, M., T.T. Lei, and T. Koike. 1998. Application of chlorophyll fluorescence to evaluate Mn tolerance of deciduous broad-leaved tree seedlings native to northern Japan. Tree Physiol. 18:135–140.

    Article  PubMed  CAS  Google Scholar 

  • Kitao, M., T.T. Lei, T. Koike, H. Tobita, and Y. Maruyama. 2000.Susceptibility to photoinhibition of three deciduous broadleaf tree species with different successional traits raised under various light regimes. Plant Cell Environ. 23:81–89.

    Article  Google Scholar 

  • Kitajima M., and W.L. Butler. 1975. Quenching of chlorophyll fluorescence and primary photochemistry in chloroplasts by dibromothymoquinone. Biochim. Biophys. Acta 376:105–115.

    Article  PubMed  CAS  Google Scholar 

  • Krause, G.H., and E. Weis. 1991. Chlorophyll fluorescence and photosynthesis: the basics. Ann. Rev. Plant Physiol. Plant Mol. Biol. 42:313–349.

    Article  CAS  Google Scholar 

  • Krause, G.H., and E. Weis. 1984. Chlorophyll fluorescence as a tool in plant physiology. II. Interpretation of fluorescence signals. Photosynth. Res. 5:139–157.

    Article  CAS  Google Scholar 

  • Krause, G.H., and K. Winter. 1996. Photoinhibition of photosynthesis in plants growing in natural tropical forest gaps: a chlorophyll fluorescence study. Bot. Acta 109:456–462.

    CAS  Google Scholar 

  • Krivosheeva, A.A., A.A. Alexeev, and P.S. Venediktov. 1992. Studies of high temperature fluorescence of chlorophyll. Mosc. Univ. Biol. Sci. Bull. 47:65–68.

    Google Scholar 

  • Laing, W., D. Greer, O. Sun, P. Beets, A. Lowe, and T. Payn. 2000. Physiological impacts of Mg deficiency in Pinus radiata: growth and photosynthesis. New Phytol. 146:47–57.

    Article  CAS  Google Scholar 

  • Larcher, W. 1994. Photosynthesis as a tool for indicating temperature stress events, p. 261–277. In: E.-D. Schulze and M.M. Caldwell (eds.), Ecophysiology of Photosynthesis. Springer, Berlin.

    Google Scholar 

  • Lefsky, M.A., W.B. Cohen, S.A. Acker, G.G. Parker, T.A. Spies, and D. Harding. Lidar. 1999. Remote sensing of the canopy structure and biophysical properties of Douglas-fir western hemlock forests. Remote Sensing Environ. 70:339–361.

    Article  Google Scholar 

  • Levitt, J. 1980. Responses of Plants to Environmental Stresses, Volume II. Academic Press, New York.

    Google Scholar 

  • Lichtenthaler, H.K. 1996. Vegetation stress: an introduction to the stress concept in plants. J. Plant Physiol. 148:4–14.

    Article  CAS  Google Scholar 

  • Lichtenthaler, H.K., and U. Rinderle. 1988. The role of chlorophyll fluorescence in the detection of stress conditions in plants. CRC Crit. Rev. Anal. Chem. 19 (Suppl):529–585.

    Google Scholar 

  • Lichtenthaler, H.K., U. Rinderle, and M. Haitz. 1989. Seasonal variations in photosynthetic activity of spruces as determined by chlorophyll fluorescence. Ann. Sci. For. 46 (Suppl): 483s–489s.

    Article  Google Scholar 

  • Lindgren K., and J.-E. Hallgren. 1993. Cold acclimation of Pinus contorta and Pinus sylvestris assessed by chlorophyll fluorescence. Tree Physiol. 13:97–106.

    Article  PubMed  Google Scholar 

  • Loik, M.E., and K.D. Holl. 1999. Photosynthetic responses to light for rainforest seedlings planted in abandoned pasture, Costa Rica. Restor. Ecol. 7:382–391.

    Article  Google Scholar 

  • Lovelock, C.E., T.A. Kusar, J.B. Skillman, and K. Winter. 1998. Photoinhibition in tropical forest understory species with short- and long-lived leaves. Funct. Ecol. 12:553–560.

    Article  Google Scholar 

  • Ludeker, W., H.G. Dahn, K.P. Gunther, and H. Schulz. 1997. Laser-induced fluorescence - a method to detect the vitality of Scots pine. Remote Sensing Environ. 68:225–236.

    Article  Google Scholar 

  • Lundmark, T., J.E. Hallgren, and J. Heden. 1988. Recovery from winter depression of photosynthesis in pine and spruce. Trees 2:110–114.

    Article  Google Scholar 

  • Luque, J., M. Cohen, R. Save, C. Biel, and I.F. Alvarez. 1999. Effects of three fungal pathogens on water relations, chlorophyll fluorescence and growth of Quercus suber L. Ann. For. Sci. 56:19–26.

    Article  Google Scholar 

  • Marler, T.E., and P.D. Lawton. 1994. Error in interpreting field chlorophyll fluorescence measurements: heat gain from solar radiation. Hort Science 29:1172–1174.

    Google Scholar 

  • Maxwell, K., and G.N. Johnson. 2000. Chlorophyll fluorescence - a practical guide. J. Expt. Bot. 51:659–668.

    Article  CAS  Google Scholar 

  • Melakeberhan, H., P.M.A. Toivonen, W.E. Vidaver, J.M. Webster, and S.L. Dube. 1991. Effect of Bursaphelenchus xylophilus on the water potential and water-splitting complex of photosystem II of Pinus sylvestris seedlings. Physiol. Mol. Plant Pathol. 38:83–91.

    Article  Google Scholar 

  • Mena-Petite, A., B. Gonzalex-Moro, C. Gonzalez-Murua, M. Lacuesta, and A. Munoz-Rueda. 2000. Sequential effects of acidic precipitation and drought on photosynthesis and chlorophyll fluorescence parameters of Pinus radiata D. Don seedlings. J. Plant Physiol. 156:84–92.

    Article  CAS  Google Scholar 

  • Methy, M., A. Olioso, and L. Trabaud. 1994. Chlorophyll fluorescence as a tool for management of plant resources. Remote Sensing Environ. 47:2–9.

    Article  Google Scholar 

  • Mohammed, G.H., W.D. Binder, and S.L. Gillies. 1995. Chlorophyll fluorescence: a review of its practical forestry applications and instrumentation. Scand. J. For. Res. 10:383–410.

    Article  Google Scholar 

  • Mohammed, G.H., and T.L. Noland. 1997. Influence of time of day and sampling methodology on chlorophyll fluorescence. Ontario Forest Research Institute (Ontario Ministry of Natural Resources, Sault Ste. Marie, Canada) Forest Research Report #142.

    Google Scholar 

  • Mohammed, G.H., T.L. Noland, W.C. Parker, and R.G. Wagner. 1997.Pre-planting physiological stress assessment to forecast field growth performance of jack pine and black spruce. For. Ecol. Manag. 92:107–117.

    Article  Google Scholar 

  • Mohammed, G.H., T.L. Noland, and R.G. Wagner. 1998. Physiological perturbation in jack pine (Pinus banksiana Lamb.) in the presence of competing herbaceous vegetation. For. Ecol. Manag. 103:77–85.

    Article  Google Scholar 

  • Moller, K. 1996. Pine on soils polluted by heavy metals: tree vitality and population dynamics of selected forest Lepidoptera. Beitr Forstwirtsch Landschaftsokologie 30:105–109.

    Google Scholar 

  • Moya, I., G. Guyot, and Y. Goulas. 1992. Remotely sensed blue and red fluorescence emission for monitoring vegetation. ISPRS J. Photogram. Remote Sensing 47:205–231.

    Article  Google Scholar 

  • Neuner, G., and P. Bannister. 1995. Frost resistance and susceptibility to ice formation during natural hardening in relation to leaf anatomy in three evergreen tree species from New Zealand. Tree Physiol. 15:371–377.

    Article  PubMed  Google Scholar 

  • Neuner, G., and O. Buchner. 1999. Assessment of foliar frost damage: a comparison of in vivo chlorophyll fluorescence with other viability tests. J. Appl. Bot. 73:50–54.

    Google Scholar 

  • Orlander, G.1993. Shading reduces both visible and invisible frost damage to Norway spruce seedlings in the field. Forestry 66:27–36.

    Article  Google Scholar 

  • Ottander, C., D. Campbell, and G. Oquist. 1995.Seasonal changes in photosystem II organisation and pigment composition in Pinus sylvestris. Planta 197:176–183.

    Article  CAS  Google Scholar 

  • Papageorgiou, G. 1975. Chlorophyll fluorescence: an intrinsic probe of photosynthesis, p. 319–371. In: Govindjee (ed.), Bioenergetics of Photosynthesis. Academic Press, New York.

    Google Scholar 

  • Parker, W.C., and G.H. Mohammed. 2000. Photosynthetic acclimation of shade-grown red pine (Pinus resinosa Ait.) seedlings to a high light environment. New For. 19:1–11.

    Article  Google Scholar 

  • Peng, C.-L., Z.-F. Lin, G.-Z. Lin, G.-H. Kong, and H.-X. Liu. 1998. Effect of tourism and industrialization on the atmospheric quality of subtropical forests and on chlorophyll fluorescence of two species of woody plants. Acta Bot. Sin. 40:270–276.

    CAS  Google Scholar 

  • Percival, G., and J. Gerritsen. 1998. The influence of plant growth regulators on root and shoot growth of containerized trees following root removal. J. Hort. Sci. Biotech. 73:353–359.

    CAS  Google Scholar 

  • Petropoulou, Y., A. Kyparissis, D. Nikolopoulos, and Y. Manetas. 1995. Enhanced UV-B radiation alleviates the adverse effects of summer drought in two Mediterranean pines under field conditions. Physiol. Plant. 94:37–44.

    Article  CAS  Google Scholar 

  • Pfundel, E. 1998. Estimating the contribution of Photosystem I to total leaf chlorophyll fluorescence. Photosynth. Res. 56:185–195.

    Article  CAS  Google Scholar 

  • Pukacki, P.M., and J. Modrzynski. 1998. The influence of ultraviolet-B radiation on the growth, pigment production and chlorophyll fluorescence of Norway spruce seedlings. Acta Physiol. Plant. 20:245–250.

    Article  CAS  Google Scholar 

  • Rinderle, U., and H.K. Lichtenthaler. 1988. The chlorophyll fluorescence ratio F690/F735 as a possible stress indicator, p. 189–197. In: H.K. Lichtenthaler (ed.), Applications of Chlorophyll Fluorescence in Photosynthesis Research, Stress Physiology, Hydrobiology and Remote Sensing. Kluwer Academic, Dordrecht, The Netherlands.

    Google Scholar 

  • Rival A., T. Beule, D. Lavergne, A. Nato, M. Havaux, and M. Puard. 1997. Development of photosynthetic characteristics in oil palm during in vitro micropropagation. J. Plant Physiol. 150:520–527.

    Article  CAS  Google Scholar 

  • Robertsdotter-Gnojek, A. 1992. Changes in chlorophyll fluorescence and chlorophyll content in suppressed Norway spruce (Picea abies (L.) Karst.) in response to release cutting. Trees 6:41–47.

    Google Scholar 

  • Roden, J.S., J.J.G. Egerton, and M.C. Ball. 1999. Effect of elevated CO2 on photosynthesis and growth of snow gum (Eucalyptus pauciflora) seedlings during winter and spring. Aust. J. Plant Physiol. 26:37–46.

    Article  Google Scholar 

  • Rosema, A., G. Cecchi, L. Pantani, B. Radicatti, M. Romuli, P. Mazzinghi, O. van Kooten, and C. Kliffen. 1992. Monitoring photosynthetic activity and ozone stress by laser induced fluorescence in trees. Intl. J. Remote Sensing 13:737–751.

    Article  Google Scholar 

  • Rosema, A., J.F.H. Snel, H. Zahn, W.F. Buurmeijer, and L.W.A. van Hove. 1998. The relation between laser-induced chlorophyll fluorescence and photosynthesis. Remote Sensing Environ. 65:143–154.

    Article  Google Scholar 

  • Rosema, A., and H. Zahn. 1997. Laser pulse energy requirements for remote sensing of chlorophyll fluorescence. Remote Sensing Environ. 62:101–108.

    Article  Google Scholar 

  • Rosenthal, S.I., and E.L. Camm. 1997. Photosynthesis decline and pigment loss during autumn foliar senescence in western larch (Larix occidentalis). Tree Physiol. 17:767–775.

    Article  PubMed  Google Scholar 

  • Roux, X. Le, S. Grand, E. Dreyer, and F.A. Daudet. 1999. Parameterization and testing of a biochemically based photosynthesis model for walnut (Juglans regid) trees and seedlings. Tree Physiol. 19:481–492.

    Article  PubMed  Google Scholar 

  • Rutherford, M.C., G.F. Midgley, and G.W. Davis. 1993. Covert symptoms of pollution stress in introduced vegetation near Cape Town. S. Afric. J. Sci. 89:50–51.

    Google Scholar 

  • Saarinen, T. 1993. Chlorophyll fluorescence, and nitrogen and pigment content of Scots pine (Pinus sylvestris) needles in polluted urban habitats. Ann. Bot. Fenn. 30:1–7.

    CAS  Google Scholar 

  • Saarinen, T., and J. Liski. 1993. The effect of industrial air pollution on chlorophyll fluorescence and pigment contents of Scots pine (Pinus sylvestris) needles. Eur. J. For. Pathol. 23:353–361.

    Article  Google Scholar 

  • Saito, Y., R. Saito, T.D. Kawahara, A. Nomura, S. Takeda, and L.G. Arvanitis. 2000. Development and performance characteristics of laser-induced fluorescence imaging lidar for forestry applications. For. Ecol. Manag. 128:129–137.

    Article  Google Scholar 

  • Sampson, P.H., C.W.G. Templeton, and S.J. Colombo. 1997. An overview of Ontario’s stock quality assessment program. New For. 13:469–487.

    Article  Google Scholar 

  • Savonen, E.M., and T. Sarjala. 1998. Effect of potassium availability on in vivo chlorophyll fluorescence and polyamines of Scots pine seedlings. Aquilo Ser. Bot. 37:7–14.

    Google Scholar 

  • Scarascia-Mugnozza, G., P. de Angelis, G. Matteucci, and R. Valentini. 1996. Long-term exposure to elevated CO2 in a natural Quercus ilex L. community: net photosynthesis and photochemical efficiency of PSII at different levels of water stress. Plant Cell Environ. 19:643–654.

    Article  CAS  Google Scholar 

  • Schmuck, G. 1990.Applications of in vivo chlorophyll fluorescence in forest decline research. Intl. J. Remote Sensing 11:1165–1177.

    Article  Google Scholar 

  • Schmutz, P., J. Siegenthaler, C. Stager, D. Tarjan, and J.B. Bucher. 1996. Long-term exposure of young spruce and beech trees to 2450-MHz microwave radiation. Sci. Total Environ. 180:43–48.

    Article  CAS  Google Scholar 

  • Schreiber, U., and W. Bilger. 1993. Progress in chlorophyll fluorescence research: major developments during the past years in retrospect. Prog. Bot. 54:151–173.

    CAS  Google Scholar 

  • Schreiber, U., U. Bilger, and C. Neubauer. 1994. Chlorophyll fluorescence as a non-intrusive indicator for rapid assessment of in vivo photosynthesis. Ecol. Stud. 100:49–70.

    CAS  Google Scholar 

  • Schwab, M., G. Noga, and W. Barthlott. 1994. Influence of high aluminum concentrations on fine structure of epicuticular waxes of spruce seedlings. Angew. Bot. 68:172–176.

    CAS  Google Scholar 

  • Seaton, G.G.R., and D.A. Walker. 1990. Chlorophyll fluorescence as a measure of photosynthetic carbon assimilation. Proc. R. Soc. Lond. B. Biol. Sci. 242:29–35.

    Article  Google Scholar 

  • Sestak, Z., and P. Siffel. 1997. Leaf-age related differences in chlorophyll fluorescence. Photosynthetica 33:347–369.

    Google Scholar 

  • Shavnin, S.A., and A.S. Fomin. 1993. Seasonal changes in the chlorophyll fluorescence of Scotch pine needles. Sov. Plant Physiol. 40:176–180.

    Google Scholar 

  • Shavnin, S.A., T.V. Kirpichnokova, and A.A. Krivosheeva. 1995. The effect of polyethylene glycol on chlorophyll fluorescence of chloroplasts isolated from Scotch pine needles. Russ. J. Plant Physiol. 42:786–790.

    CAS  Google Scholar 

  • Shavnin. S., S. Maurer, R. Matyssek, W. Bilger, and C. Scheidegger. 1999. The impact of ozone fumigation and fertilization on chlorophyll fluorescence of birch leaves (Betula pendula). Trees 14:10–16.

    Article  Google Scholar 

  • Smith, W., and G.H. Mohammed. 1997. Inoculation with mycorrhizal fungi (Hebeloma spp.) can increase drought stress resistance and improve field performance of jack pine, black spruce, and white spruce. Ontario Forest Research Institute (Ontario Ministry of Natural Resources, Sault Ste. Marie, Canada) Forest Research Report #145.

    Google Scholar 

  • Solhaug, K.A., and J. Haugen. 1998. Seasonal variation of photoinhibition of photosynthesis in bark from Populus tremula L. Photosynthetica 35:411–417.

    Article  Google Scholar 

  • Sowinska, M., F. Heisel, J.A. Miehe, M. Lang, H.K. Lichtenthaler, and F. Tomasini. 1996. Remote sensing of plants by streak camera lifetime measurements of the chlorophyll a emission. J. Plant Physiol. 148:638–644.

    Article  CAS  Google Scholar 

  • Sprtova, M., L. Nedbal, and M.V. Marek. 2000. Effect of enhanced UV-B radiation on chlorophyll a fluorescence parameters in Norway spruce needles. J. Plant Physiol. 156:234–241.

    Article  CAS  Google Scholar 

  • Spunda, V., M. Cajanek, J. Kalina, I. Lachetova, M. Sprtova, and M.V. Marek. 1998. Mechanistic differences in utilization of absorbed excitation energy within photosynthetic apparatus of Norway spruce induced by the vertical distribution of photosynthetically active radiation through the tree crown. Plant Sci. 133:155–165.

    Article  CAS  Google Scholar 

  • Strand, M. 1997. Effect of mineral nutrient content on oxygen exchange and chlorophyll a fluorescence in needles of Norway spruce. Tree Physiol. 17:221–230.

    Article  PubMed  CAS  Google Scholar 

  • Strand, M., and G. Oquist. 1988. Effects of frost hardening, dehardening and freezing stress on in vivo chlorophyll fluorescence of seedlings of Scots pine (Pinus sylvestris L.). Plant Cell Environ. 11:231–238.

    Article  CAS  Google Scholar 

  • Theisen, A.F. 1988. Fluorescence changes of a drying maple leaf observed in the visible and near-infrared, p. 197–201. In: H.K. Lichtenthaler (ed.), Applications of Chlorophyll Fluorescence in Photosynthesis Research, Stress Physiology, Hydrobiology and Remote Sensing. Kluwer Academic, Dordrecht, The Netherlands.

    Google Scholar 

  • Theisen, A.F., L. Jarrell, P.L. Kebabian, and A. Freedman. 1998. Remote detection of vegetation stress using sunlight-excited fluorescence. Proc. 1st Intl. Conf. Geospatial Information in Agriculture and Forestry, p. 11–547 - II-552. Lake Buena Vista, Florida

    Google Scholar 

  • Theisen, A.F., B.N. Rock, and R.T. Eckert. 1994. Detection of changes in steady-state chlorophyll fluorescence in Pinus strobus following short-term ozone exposure. J. Plant Physiol. 144:410–419.

    Article  CAS  Google Scholar 

  • Valentini, R., G. Cecchi, P. Mazzinghi, G.S. Mugnozza, G. Agati, M. Bazzani, P. Angelis, F. Fusi, G. Matteucci, V. Raimondi, and G. Scarascia-Mugnozza. 1994. Remote sensing of chlorophyll a fluorescence of vegetation canopies: 2. Physiological significance of fluorescence signal in response to environmental stresses. Remote Sensing Environ. 47:29–35.

    Article  Google Scholar 

  • Venediktov, P.S., Y.V. Kazimirko, N. Konev, T.E. Krendeleva, G.P. Kukarskikh, O.G. Lavrukhina, V.V. Makarova, S.I. Pogosyan, and A.B. Rubin. 1998. Pulse fluorometer for remote measuring of chlorophyll fluorescence from laboratory plant stands. Russ. J. Plant Physiol. 45:820–829.

    CAS  Google Scholar 

  • Verhoeven, A.S., W.W. III. Adams, and B. Demmig-Adams. 1996.Close relationship between the state of the xanthophyll cycle pigments and photosystem II efficiency during recovery from winter stress. Physiol. Plant. 96:567–576.

    Article  CAS  Google Scholar 

  • Vidaver, W., W. Binder, R.C. Brooke, G.R. Lister, and P.M.A. Toivonen. 1989. Assessment of photosynthetic activity of nursery-grown Picea glauca seedlings using an integrating fluorometer to monitor variable chlorophyll fluorescence. Can. J. For. Res. 19:1478– 1482.

    Article  Google Scholar 

  • Wagner, J., S.P. Menendez, and W. Larcher. 1991. Bioclimate and productive potential of Quercus ilex L. at its northern-most distribution limit. Part HI. Morphological and functional adaptations of leaves to the light regime. Stud. Trentini. Sci. Nat. Acta Biol. 68:37–51.

    Google Scholar 

  • Welander, N.T., P. Gemmel, O. Hellgren, and B. Ottosson. 1994. The consequences of freezing temperatures followed by high irradiance on in vivo chlorophyll fluorescence and growth in Picea abies. Physiol. Plant. 91:121–127.

    Article  CAS  Google Scholar 

  • Werner, C., and O. Correia. 1996. Photoinhibition in cork-oak leaves under stress: influence of the bark-stripping on the chlorophyll fluorescence emission in Quercus suber L. Trees 10:288–292.

    Google Scholar 

  • Westin, J., L.G. Sundblad, and J.E. Hallgren. 1995. Seasonal variation in photochemical activity and hardiness in clones of Norway spruce (Picea abies). Tree Physiol. 15:685–689.

    Article  PubMed  CAS  Google Scholar 

  • Wulff, A., L. Sheppard, and I. Leith. 1994. Evaluation of electrolyte leakage, chlorophyll fluorescence and ultrastructural techniques for detecting effects of acid mist on frost hardiness of Sitka spruce shoots. Environ. Expt. Bot. 34:261–273.

    Article  Google Scholar 

  • Zarco-Tejada, P.J., J.R. Miller, G.H. Mohammed, T.L. Noland, and P.H. Sampson. 2002. Vegetation stress detection through chlorophyll a+b estimation and fluorescence effects on hyperspectral imagery. J. Environ. Quality 31:1433–1441.

    Article  CAS  Google Scholar 

  • Zarco-Tejada, P.J., J.R. Miller, G.H. Mohammed, T.L. Noland., and P.H. Sampson. 2001. Estimation of chlorophyll fluorescence under natural illumination from hyperspectral data. Intl. J. Appl. Earth Observation and Geoinformation, Special Issue on Applications of Imaging Spectroscopy 3:321–327.

    Article  Google Scholar 

  • Zarco-Tejada, P.J., J.R. Miller, G.H. Mohammed, and T.L. Noland. 2000a. Chlorophyll fluorescence effects on vegetation apparent reflectance. I. Leaf-level measurements and model simulation. Remote Sensing Environ. 74:582–595.

    Article  Google Scholar 

  • Zarco-Tejada, P.J., J.R. Miller, G.H. Mohammed, T.L. Noland, and P.H. Sampson. 2000b. Chlorophyll fluorescence effects on vegetation apparent reflectance. II. Laboratory and airborne canopy-level measurements with hyperspectral data. Remote Sensing Environ. 74:596–608.

    Article  Google Scholar 

  • Ziegler-Jons, A., H. Kammerbauer, S. Drenkard, B. Hock, and D. Knoppik. 1990. Independent photosynthetic response of exposed and unexposed twigs of the same spruce tree to car exhaust. Eur. J. For. Pathol. 20:376–380.

    Article  Google Scholar 

  • Zimmerman, R., and K.P. Gunther. 1986. Laser-induced chlorophyll a fluorescence of terrestrial plants, p. 1609–1613. In: Proc. IGARSS, Zurich, Switzerland; Paris: European Space Agency.

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2003 Springer Science+Business Media New York

About this chapter

Cite this chapter

Mohammed, G.H., Zarco-Tejada, P., Miller, J.R. (2003). Applications of Chlorophyll Fluorescence in Forestry and Ecophysiology. In: DeEll, J.R., Toivonen, P.M.A. (eds) Practical Applications of Chlorophyll Fluorescence in Plant Biology. Springer, Boston, MA. https://doi.org/10.1007/978-1-4615-0415-3_3

Download citation

  • DOI: https://doi.org/10.1007/978-1-4615-0415-3_3

  • Publisher Name: Springer, Boston, MA

  • Print ISBN: 978-1-4613-5065-1

  • Online ISBN: 978-1-4615-0415-3

  • eBook Packages: Springer Book Archive

Publish with us

Policies and ethics