Detection of vegetation stress via a new high resolution fluorescence imaging system

Summary The UV-laser ( λ 355 nm) induced fluorescence emission spectra of green leaves comprise the blue(F440) and green (F520) fluorescence bands as well as the red (F690) and far-red (F740) chlorophyll fluorescence emission bands. Based on the four UV-laser induced fluorescence bands blue, green, red and farred a high resolution fluorescence imaging system was established, which allows a fast and large scale screening of fluorescence gradients and local disturbances in fluorescence emission over the whole leaf surface. The new imaging method not only permits to screen leaves by means of images in four fluorescence bands ( LIF images ) but, in addition, via images of the fluorescence ratios blue/red (F440/F690), blue/farred (F440/F740), the chlorophyll fluorescence ratio red/far-red (F690/F740) and the ratio blue/green (F440/F520) ( LIF ratio images ). By fluorescence imaging we could prove that in aurea tobacco the major part of the leaves' blue and green fluorescence is emitted from the main and side leave veins, whereas the major part of the leaves' red and far-red chlorophyll fluorescence is emitted from the vein-free leaf regions, which also have the highest chlorophyll content. A smaller proportion of the aurea tobacco leaves' blue-green fluorescence emission is derived from the cell walls of epidermis cells. The fluorescence ratios blue/red and blue/far-red are very sensitive to environmental changes, and thus permit early stress and strain detection in plants, and the evaluation of damage to the photosynthetic apparatus. Via monitoring the increase in chlorophyll fluorescence LIF images allow to detect differences in the time-dependent uptake of diuron and the progressing inhibition of photosynthetic electron transport in the treated leaf part. The novel fluorescence imaging technique sets a new dimension for early stress detection in the photosynthetic apparatus and in plants. It has many advantages over the previously applied point-data measurements of selected leaf points using conventional spectrofluorometers. The new fluorescence imaging system proved to be very suitable for remote sensing of plants in the near distance, and can be further developed for far distance remote sensing of the state of health of terrestrial vegetation. Some examples in the many possible ways of computer-aided fluorescence data processing (formation of different fluorescence ratios, screening of fluorescence profiles, histogramme plotting) are indicated.

[1]  E. Govindje,et al.  Sixty-Three Years Since Kautsky: Chlorophyll a Fluorescence , 1995 .

[2]  Hartmut K. Lichtenthaler,et al.  Decrease of the chlorophyll fluorescence ratio F690/F730 during greening and development of leaves , 1990, Radiation and environmental biophysics.

[3]  G. Krause,et al.  The Photosynthetic Apparatus and Chlorophyll Fluorescence. An Introduction , 1988 .

[4]  Application of the Karlsruhe CCD-OMA LIDAR-Fluorosensor in Stress Detection of Plants , 1996 .

[5]  H. Lichtenthaler,et al.  Fluorescence Emission Spectra of Paraquat ResistantConyza canadensis During the Chlorophyll Fluorescence Induction as Determined by the CCD-OMA System , 1996 .

[6]  H. Lichtenthaler.  Vegetation stress : an introduction to the stress concept in plants , 1996 .

[7]  H. Lichtenthaler,et al.  Chlorophyll Fluorescence Spectra of Leaves as Induced by Blue Light and Red Laser Light , 1988 .

[8]  H. Lichtenthaler,et al.  Studies on the constancy of the blue and green fluorescence yield during the chlorophyll fluorescence induction kinetics (Kautsky effect) , 1993, Radiation and environmental biophysics.

[9]  H. Lichtenthaler,et al.  Increase of the chlorophyll fluorescence ratio F690/F735 during the autumnal chlorophyll breakdown , 1992, Radiation and environmental biophysics.

[10]  Hartmut K. Lichtenthaler,et al.  In Vivo Chlorophyll Fluorescence as a Tool for Stress Detection in Plants , 1988 .

[11]  H. Lichtenthaler,et al.  Fluorescence emission spectra of plant leaves and plant constituents , 1991, Radiation and environmental biophysics.

[12]  Hartmut K. Lichtenthaler,et al.  The Role of Chlorophyll Fluorescence in The Detection of Stress Conditions in Plants , 1988 .

[13]  K. LichtenthalerH,et al.  The Kautsky effect: 60 years of chlorophyll fluorescence induction kinetics. , 1992 .

[14]  J. McMurtrey,et al.  Laser-induced fluorescence of green plants. 1: A technique for the remote detection of plant stress and species differentiation. , 1984, Applied optics.

[15]  Hartmut K. Lichtenthaler,et al.  Changes in the Blue-Green and Red Fluorescence-Emission Spectra of Beech Leaves during the Autumnal Chlorophyll Breakdown , 1991 .

[16]  R. Hartley,et al.  Detection of bound ferulic acid in cell walls of the Gramineae by ultraviolet fluorescence microscopy , 1976, Nature.

[17]  H. Lichtenthaler,et al.  Blue, green, and red fluorescence emission signatures of green, etiolated, and white leaves☆ , 1994 .

[18]  G. Schmid.  [15] Origin and properties of mutant plants: Yellow tobacco , 1971 .

[19]  Francine Heisel,et al.  Blue, Green and Red Fluorescence Signatures and Images of Tobacco Leaves* , 1994 .

[20]  H. K. Lichtenthaler,et al.  A CCD-OMA device for the measurement of complete chlorophyll fluorescence emission spectra of leaves during the fluorescence induction kinetics , 1992, Radiation and environmental biophysics.

[21]  H. Lichtenthaler,et al.  Light-Induced Accumulation and Stability of Chlorophylls and Chlorophyll-Proteins during Chloroplast Development in Radish Seedlings , 1981 .

[22]  H. Lichtenthaler.  CHLOROPHYLL AND CAROTENOIDS: PIGMENTS OF PHOTOSYNTHETIC BIOMEMBRANES , 1987 .

[23]  H. Lichtenthaler,et al.  Changes of Chlorophyll Fluorescence Signatures during Greening of Etiolated Barley Seedlings as Measured with the CCD-OMA Fluorometer , 1996 .

[24]  Francine Heisel,et al.  Fluorescence Imaging of Water and Temperature Stress in Plant Leaves , 1996 .

[25]  Studies on the localization and spectral characteristics of the fluorescence emission of differently pigmented wheat leaves , 1993 .

[26]  H. Lichtenthaler,et al.  Characterization of the laser-induced blue, green and red fluorescence signatures of leaves of wheat and soybean grown under different irradiance. , 1993, Physiologia plantarum.

[27]  Hartmut K. Lichtenthaler,et al.  Reflectance and Chlorophyll Fluorescence Signatures of Leaves , 1988 .

[28]  G. Krause,et al.  Chlorophyll Fluorescence and Photosynthesis: The Basics , 1991 .