Chlorophyll fluorescence imaging of photosynthetic activity with the flash-lamp fluorescence imaging system (original) (raw)
Related papers
Chlorophyll fluorescence imaging of photosynthetic activity in sun and shade leaves of trees
Photosynthesis Research, 2007
The differences in pigment levels, photosynthetic activity and the chlorophyll fluorescence decrease ratio R Fd (as indicator of photosynthetic rates) of green sun and shade leaves of three broadleaf trees (Platanus acerifolia Willd., Populus alba L., Tilia cordata Mill.) were compared. Sun leaves were characterized by higher levels of total chlorophylls a + b and total carotenoids x + c as well as higher values for the weight ratio chlorophyll (Chl) a/b (sun leaves 3.23-3.45; shade leaves: 2.74-2.81), and lower values for the ratio chlorophylls to carotenoids (a + b)/(x + c) (with 4.44-4.70 in sun leaves and 5.04-5.72 in shade leaves). Sun leaves exhibited higher photosynthetic rates P N on a leaf area basis (mean of 9.1-10.1 lmol CO 2 m -2 s -1 ) and Chl basis, which correlated well with the higher values of stomatal conductance G s (range 105-180 mmol m -2 s -1 ), as compared to shade leaves (G s range 25-77 mmol m -2 s -1 ; P N : 3.2-3.7 lmol CO 2 m -2 s -1 ). The higher photosynthetic rates could also be detected via imaging the Chl fluorescence decrease ratio R Fd , which possessed higher values in sun leaves (2.8-3.0) as compared to shade leaves (1.4-1.8). In addition, via R Fd images it was shown that the photosynthetic activity of the leaves of all trees exhibits a large heterogeneity across the leaf area, and in general to a higher extent in sun leaves than in shade leaves.
2015
Analyzing the changes that occur in the photosynthetic machinery of plants is one of the most informative approaches for evaluation of the plant physiological state, their stress reactions, productivity and the adaptive mechanisms that develop in order to protect the plant in a changing environment. An informative method for detection and analyzing of the photosynthetic process is measuring the chlorophyll a fluorescence emitted from leaves. Illumination of a plant sample induces a rise in the chlorophyll a fluorescence that draws characteristic induction curves which carry broad spectrum of data about every step of the photosynthetic process. Chlorophyll a fluorescence gives two types of signals – prompt (PF) and delayed chlorophyll fluorescence (DF). The Multifunctional Plant Efficiency Analyzer (MPEA), developed by Hansatech is constructed to measure both simultaneously in only one measurement, but as the initial steps of their kinetics overlap they cannot be recorded together wh...
PLANT PHYSIOLOGY, 1989
The distribution of photosynthetic activity over the area of a leaf and its change with time was determined (at low partial pressure of 02) by recording images of chlorophyll fluorescence during saturating light flashes. Simultaneously, the gas exchange was being measured. Reductions of local fluorescence intensity quantitatively displayed the extent of nonphotochemical quenching; quench coefficients, qN, were computed pixel by pixel. Because rates of photosynthetic electron transport are positively correlated with (1 -qN), computed images of (1 -qN) represented topographies of photosynthetic activity. Following application of abscisic acid to the heterobaric leaves of Xanthium strumarium L., clearly delineated regions varying in nonphotochemical quenching appeared that coincided with areoles formed by minor veins and indicated stomatal closure in groups.
Radiation and Environmental Biophysics, 1992
A new device for the measurement of complete laser induced fluorescence emission spectra (maxima near 690 and 735 nm) of leaves during the induction of the chlorophyll fluorescence is described. In this the excitation light (cw He/Ne laser, 632.8 nm) is switched on by a fast electro-mechanical shutter which provides an opening time of 1 ms. The emitted fluorescence is imaged onto the entrance slit of a multichannel spectrograph through a red cut-off filter (> 645 nm). A charge coupled device (CCD) sensor with 2048 elements simultaneously detects the complete chlorophyll fluorescence emission spectrum in the 650–800 nm wavelength range. Scanning is accomplished electronically and the integration time for a complete fluorescence emission spectrum can be selected from 10 ms up to 260 ms. Shutter, detector system and data acquisition are controlled by an IBM-PC/AT compatible computer. A maximum of 32 spectra can be measured at selected times during the fluorescence induction kinetics with the shortest time resolution of 10 ms. The instrument permits the determination of various fluorescence parameters:a) the rise-time of the fluorescence to the maximum level fm,b) the changes in the shape of the fluorescence emission spectra during the induction kinetics,c) the induction kinetics in the fluorescence ratio F690/F735 as well asd) the fluorescence decrease ratio Rfd at any wavelength between 650 to 800 nm. These fluorescence parameters provide information about the functioning of photosynthesis. The ratio F690/F735 allows the non-destructive determination of the chlorophyll content of leaves. The application of this instrument in ecophysiological research and stress physiology of plants is outlined.
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...
High resolution imaging of photosynthetic activities of tissues, cells and chloroplasts in leaves
Journal of Experimental Botany, 2001
Through imaging of chlorophyll fluorescence, it is possible to produce parameterized fluorescence images that estimate the operating quantum efficiency of photosystem II (PSII) photochemistry and which can be used to reveal heterogeneous patterns of photosynthetic performance within leaves. The operating quantum efficiency of PSII photochemistry is dependent upon the effective absorption crosssection of the light-harvesting system of PSII and the photochemical capacity of PSII. The effective absorption cross-section is decreased by the process of down-regulation, which is widely thought to operate within the pigment matrices of PSII and which results in non-photochemical quenching of chlorophyll fluorescence. The photochemical capacity is non-linearly related to the proportion of PSII centres in the`open' state and results in photochemical quenching of chlorophyll fluorescence. Examples of heterogeneity of the operating quantum efficiency of PSII photochemistry during the induction of photosynthesis in maize leaves and in the chloroplast populations of stomatal guard cells of a leaf of Tradescantia albifora are presented, together with analyses of the factors determining this heterogeneity. A comparison of the operating quantum efficiency of PSII photochemistry within guard cells and adjacent mesophyll cells of Commelina communis is also made, before and after stomatal closure through a change in ambient humidity.
Photosynthesis Research, 2013
The principles of the chlorophyll (Chl) fluorescence induction kinetics (known as Kautsky effect) and their change by the photosystem II herbicide diuron are presented together with the Chl fluorescence emission spectra of a normal and diuron-inhibited leaf. By imaging the Chl fluorescence emission of green leaves the successive uptake of diuron and the concomitant loss of photosynthetic quantum conversion from the leaf base to the leaf tip are documented. Keywords Chlorophyll fluorescence decrease ratio R Fd Á Digitalis purpurea Á Herbicide action Á Phaseolus vulgaris Á Photosystem II herbicide Abbreviations Chl Chlorophyll F690/F740 Ratio of the two peaks of chlorophyll fluorescence emission spectra Fd Chl fluorescence decrease FL-FIS Flash-lamp fluorescence imaging system Fm and Fs Maximum and steady-state Chl fluorescence R Fd Variable Chl fluorescence decrease ratio
Acta Physiologiae Plantarum, 2016
Plants living under natural conditions are exposed to many adverse factors that interfere with the photosynthetic process, leading to declines in growth, development, and yield. The recent development of Chlorophyll a fluorescence (ChlF) represents a potentially valuable new approach to study the photochemical efficiency of leaves. Specifically, the analysis of fluorescence signals provides detailed information on the status and function of Photosystem II (PSII) reaction centers, lightharvesting antenna complexes, and both the donor and acceptor sides of PSII. Here, we review the results of fast ChlF analyses of photosynthetic responses to environmental stresses, and discuss the potential scientific and practical applications of this innovative methodology. The recent availability of portable devices has significantly expanded the potential utilization of ChlF techniques, especially for the purposes of crop phenotyping and monitoring.