Conclusive remarks. Reliability and comparability of chlorophyll fluorescence data from several field teams (original) (raw)
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2014
Two field exercises were carried out to compare chlorophyll a fluorescence measurements taken in the field by field teams working on the same project. In the first exercise (2007, Passo Pura, Ampezzo, Udine, Northern Italy) the operators took measurements on the same leaf areas (maintaining fixed leaf clips); in the second (2009, Monterotondo Marittimo, Grosseto, Central Italy) the teams worked independently, but addressing a common research question. The results of the first exercise showed that: (a) F V /F M was stable and had little variation among teams and instruments; (b) the results from the different teams correlated well; (c) the most suitable parameters of fast kinetics analysis are those measured on the normalized fluorescence transients. In the second exercise, when the teams worked independently, the results were much more variable and the correlations between measurements of different operators were weak. These results suggest that field chlorophyll a fluorescence measurements taken by different teams/operators can be comparable only if particular care is taken to the internal variability of the samples and a standardized sampling strategy is applied. A statistically sound representation of a population can be then reached.
Remote Sensing of …, 1999
A remote sensing technique is presented to estimate the Major, 1988). The relationship F 685 /F 735 vs. Chl was expressed by a power function F 685 /F 735 ϭmChl Ϫn . For dif-chlorophyll content in higher plants. The ratio between chlorophyll fluorescence at 735 nm and in the range 700ferent plant species, the coefficients m and n were different, but the common features of the relationships were 710 nm, F 735 /F 700 was found to be linearly proportional to the chlorophyll content (with determination coeffii) high sensitivity of the ratio to low to medium Chl content (from near zero to about 100-150 mg m Ϫ2 -slightly cient, r 2 , more than 0.95), and, thus, this ratio can be used as a precise indicator of chlorophyll content in plant green and yellowish-green leaves); and ii) the ratio F 685 / F 735 leveled off at moderate to high Chl content and its leaves. This new chlorophyll fluorescence ratio indicates chlorophyll levels with high precision-the error in chlosensitivity to ChlϾ200 mg m Ϫ2 was fairly low. Chlorophyll fluorescence depends to a great extent rophyll prediction over a wide range of chlorophyll content (from 41 to 675 mg m Ϫ2 ) was less than 40 mg m Ϫ2 .
Remote Sensing of Environment, 1999
A remote sensing technique is presented to estimate the chlorophyll content in higher plants. The ratio between chlorophyll fluorescence at 735 nm and in the range 700–710 nm, F735/F700 was found to be linearly proportional to the chlorophyll content (with determination coefficient, r2, more than 0.95), and, thus, this ratio can be used as a precise indicator of chlorophyll content in plant leaves. This new chlorophyll fluorescence ratio indicates chlorophyll levels with high precision- the error in chlorophyll prediction over a wide range of chlorophyll content (from 41 to 675 mg m−2) was less than 40 mg m−2. The technique was tested and validated in three plant species: beech (Fagus sylvatica L.), elm (Ulmus minor Miller), and wild vine (Parthenocissus tricuspidata L.).
Remote Sensing of Environment, 1994
Induction kinetics of chlorophyll fluorescence (the Kautsky effect) and delayed fluorescence (DF) of some cold climate species were studied in both laboratory and in situ experiments to assess their vlaue as indicators of plant health. Experiments included studies of natural variability of fluorescence in connection with the seasonal leaf maturation process, as well as the influence of environmental stress factors, such as ozone. It was found that parameters of induction curves (normalized variable fluorescence, time of its half decrease) could be used as indicators of plant health. No significant differences have been elicited between the information content of the Kautsky effect and induction curves of DF as tools for remote sensing. It is suggested that measurements of the single decay curves of DF are preferable for remote estimation of photosynthetic capacity.
Remote Sensing, 2019
Imaging and non-imaging spectroscopy employed in the field and from aircraft is frequently used to assess biochemical, structural, and functional plant traits, as well as their dynamics in an environmental matrix. With the increasing availability of high-resolution spectroradiometers, it has become feasible to measure fine spectral features, such as those needed to estimate sun-induced chlorophyll fluorescence (F), which is a signal related to the photosynthetic process of plants. The measurement of F requires highly accurate and precise radiance measurements in combination with very sophisticated measurement protocols. Additionally, because F has a highly dynamic nature (compared with other vegetation information derived from spectral data) and low signal intensity, several environmental, physiological, and experimental aspects have to be considered during signal acquisition and are key for its reliable interpretation. The European Cooperation in Science and Technology (COST) Actio...
Photosynthetica, 2021
We provide here a general introduction on chlorophyll (Chl) a fluorescence, then we present our measurements on fast (< 1 s) induction curves (the so-called OJIP transients) on dark-adapted intact leaves of Arabidopsis thaliana, under five different light intensities [in the range of ~ 500 to ~ 3,000 µmol(photons) m‒2 s‒1] using two different instruments: Handy PEA (Hansatech Instruments, UK; excitation light, 650 nm) and FluorPen (model FP-110; Photon Systems Instruments, The Czech Republic; excitation light, 470 nm). We then discuss the observed differences in the OJIP curves, as well as in Fo (F20μs, F50μs, or the extrapolated Ft→0), FP (the peak), and the ratios FP/Fo, and Fv (= FP ‒ Fo)/FP in terms of differences in excitation light intensity and absorptance (or absorbance) of the excitation light by the leaves, and other factors, as well as the data available in the literature. We suggest that such measurements be accompanied, in the future, by parallel measurements on Chl ...
Frequently asked questions about chlorophyll fluorescence, the sequel
Photosynthesis Research, 2016
Using chlorophyll (Chl) a fluorescence many aspects of the photosynthetic apparatus can be studied, both in vitro and, noninvasively, in vivo. Complementary techniques can help to interpret changes in the Chl a fluorescence kinetics. Kalaji et al. (Photosynth Res 122:121-158, 2014a) addressed several questions about instruments, methods and applications based on Chl a fluorescence. Here, additional Chl a fluorescence-related topics are discussed again in a question and answer format. Examples are the effect of connectivity on photochemical quenching, the correction of F V /F M values for PSI fluorescence, the energy partitioning concept, the interpretation of the complementary area, probing the donor side of PSII, the assignment of bands of 77 K fluorescence emission spectra to fluorescence emitters, the relationship between prompt and delayed fluorescence, potential problems when sampling tree canopies, the use of fluorescence parameters in QTL studies, the use of Chl a fluorescence in biosensor Hazem M. Kalaji and Gert Schansker have contributed equally to this paper.
Remote Sensing of Environment, 1994
This article presents instruments and techniques, used in several vegetation monitoring experiments. Simultaneous monitoring was performed with different approaches, including fluorescence lidar and passive remote sensing, leaf level reflectance, and laser fluorimetry, and compared with physiological measurements. Most of the instrumentation described was designed and built for this application. Experiments were carried out in the laboratory and in the field, to investigate the relationship between chlorophyll fluorescence spectra and plant ecophysiology. Remote sensing, spectroscopy, and ecophysiology data were then collected by an intensive research team, joining different experiences and working in national and international projects.