[show abstract][hide abstract] ABSTRACT: These species are good examples of ecophysiological divergence regarding the plant water relations and the adaptations to the conditions of water regime in the habitat. Aim of this study was to investigation of different ecological conditions of these species in their habitats and to comparison of photosynthetic activity responses and relative water content (RWC) during dehydration and rehydration cycle. R. serbica inhabits in more humid and cooler habitats, primarily sheltered by forest canopy, while R. nathaliae is found in more open, drier and warmer habitats. In this case, our results of RWC showed that dehydration of R. serbica leaves was very slow, especially in the first stage. On other hand, rehydration was restored rapidly in R. nathaliae. Therefore, the preservation of the RWC in R. serbica more than in R. nathaliae, in first stage of dehydration, could be as a result of these conditions. During dehydration when RWC were more than 40 %, photochemical efficiency of PSII for photochemistry, the Fv/Fm ratio, decreased about 40 % in R. nathaliae plants, but a strong reduction with 60 % was recorded for R. serbica. Following rehydration, the Fv/Fm ratio recovered more rapidly in R. nathaliae. Moreover, the present results suggest that R. nathaliae was more resistant during desiccation than R. serbica, and recovered more rapidly to normal physiological activity after rewatering.
5th International Syposium of Ecologist of Montenegro, Tivat, Montenegro; 10/2013
[show abstract][hide abstract] ABSTRACT: The desiccation-tolerant plants of the R. serbica and R. nathaliae are resurrection plants which are able to fully recover their physiological function after anabiosis. A comparison of chlorophyll fluorescence imaging and photosynthetic pigment contents responses of R. serbica and, for the first time, R. nathaliae to dehydration and rehydration were investigated. For this purpose, plants after collection from their natural habitats were kept fully watered for 14 days at natural condition. The experiment was conducted with mature leaves of both species. R. serbica and R. nathaliae plants were dehydrated to 5.88 % and 7.87 % relative water content (RWC) by withholding water for 15 days, afterwards the plants were rehydrated for 72 hours to 94.67 % and 97.02 % RWC. During desiccation, R. serbica plants preserved the chlorophyll content about 84 %, while R. nathaliae about 90 %. During dehydration when RWC were more than 40 %, photochemical efficiency of PSII for photochemistry, the Fv/Fm ratio, decreased about 40 % in R. nathaliae plants, but a strong reduction with 60 % was recorded for R. serbica. Following rehydration, the Fv/Fm ratio recovered more rapidly in R. nathaliae. The higher photosynthetic rates could also be detected via imaging the chlorophyll fluorescence decrease ratio Rfd, which possessed higher values after rehydration leaves of R. nathaliae as compared to R. serbica. The results showed that the photosynthetic activity and chlorophyll contents after rehydration are recovered more rapidly in R. nathaliae in comparison to R. serbica.
Physiology and Molecular Biology of Plants 07/2013; 19(3):333-341.
[show abstract][hide abstract] ABSTRACT: The chlorophyll (Chl) fluorescence induction kinetics, net photosynthetic CO2 fixation rates P N, and composition of photosynthetic pigments of differently light exposed leaves of several trees were comparatively measured to determine the differences in photosynthetic activity and pigment adaptation of leaves. The functional measurements were carried out with sun, half-shade and shade leaves of seven different trees species. These were: Acer platanoides L., Ginkgo biloba L., Fagus sylvatica L., Platanus x acerifolia Willd., Populus nigra L., Quercus robur L., Tilia cordata Mill. In three cases (beech, ginkgo, and oak), we compared the Chl fluorescence kinetics and photosynthetic rates of blue-shade leaves of the north tree crown receiving only blue sky light but no direct sunlight with that of sun leaves. In these cases, we also determined in detail the pigment composition of all four leaf types. In addition, we determined the quantum irradiance and spectral irradiance of direct sunlight, blue skylight as well as the irradiance in half shade and full shade. The results indicate that sun leaves possess significantly higher mean values for the net CO2 fixation rates P N (7.8-10.7 μmol CO2 m(-2) s(-1) leaf area) and the Chl fluorescence ratio R Fd (3.85-4.46) as compared to shade leaves (mean P N of 2.6-3.8 μmol CO2 m(-2) s(-1) leaf area.; mean R Fd of 1.94-2.56). Sun leaves also exhibit higher mean values for the pigment ratio Chl a/b (3.14-3.31) and considerably lower values for the weight ratio total chlorophylls to total carotenoids, (a + b)/(x + c), (4.07-4.25) as compared to shade leaves (Chl a/b 2.62-2.72) and (a + b)/(x + c) of 5.18-5.54. Blue-shade and half-shade leaves have an intermediate position between sun and shade leaves in all investigated parameters including the ratio F v/F o (maximum quantum yield of PS2 photochemistry) and are significantly different from sun and shade leaves but could not be differentiated from each other. The mean values of the Chl fluorescence decrease ratio R Fd of blue-shade and half-shade leaves fit well into the strong linear correlation with the net photosynthetic rates P N of sun and shade leaves, thus unequivocally indicating that the determination of the Chl fluorescence decrease ratio R Fd is a fast and indirect measurement of the photosynthetic activity of leaves. The investigations clearly demonstrate that the photosynthetic capacity and pigment composition of leaves and chloroplasts strongly depend on the amounts and quality of light received by the leaves.
Photosynthesis Research 05/2013; · 3.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: With a flash-lamp chlorophyll (Chl) fluorescence imaging system (FL-FIS) the photosynthetic activity of several thousand image
points of intact shade and sun leaves of beech were screened in a non-destructive way within a few seconds. The photosynthetic
activity was determined via imaging the Chl fluorescence at maximum Fp and steady state fluorescence Fs of the induction kinetics (Kautsky effect) and by a subsequent determination of the images of the fluorescence decrease ratio
RFd and the ratio Fp/Fs. Both fluorescence ratios are linearly correlated to the photosynthetic CO2 fixation rates. This imaging method permitted to detect the gradients in photosynthetic capacity and the patchiness of photosynthetic
quantum conversion across the leaf. Sun leaves of beech showed a higher photosynthetic capacity and differential pigment ratios
(Chl a/b and Chls/carotenoids) than shade leaves. Profile analysis and histogram of the Chl fluorescence yield and the Chl fluorescence
ratios allow to quantify the differences in photosynthetic activity between different leaf parts and between sun and shade
leaves with a high statistical significance.
carotenoid and chlorophyll contents–
–flash radiation pulses–fluorescence decrease ratio–pigment ratios–vitality index
[show abstract][hide abstract] ABSTRACT: Fluorescence images of leaves of sugar beet plants (Beta vulgaris L. cv. Patricia) grown on an experimental field with different fertilisation doses of nitrogen [0, 3, 6, 9, 12, 15 g(N) m−2] were taken, applying a new multicolour flash-lamp fluorescence imaging system (FL-FIS). Fluorescence was excited by the
UV-range (280–400 nm, λmax = 340 nm) of a pulsed Xenon lamp. The images were acquired successively in the four fluorescence bands of leaves near 440,
520, 690, and 740 nm (F440, F520, F690, F740) by means of a CCD-camera. Parallel measurements were performed to characterise the physiological state of the leaves (nitrogen
content, invert-sugars, chlorophylls and carotenoids as well as chlorophyll fluorescence induction kinetics and beet yield).
The fluorescence images indicated a differential local patchiness across the leaf blade for the four fluorescence bands. The
blue (F440) and green fluorescence (F520) were high in the leaf veins, whereas the red (F690) and far-red (F740) chlorophyll (Chl) fluorescences were more pronounced in the intercostal leaf areas. Sugar beet plants with high N supply
could be distinguished from beet plants with low N supply by lower values of F440/F690 and F440/F740. Both the blue-green fluorescence and the Chl fluorescence rose at a higher N application. This increase was more pronounced
for the Chl fluorescence than for the blue-green one. The results demonstrate that fluorescence ratio imaging of leaves can
be applied for a non-destructive monitoring of differences in nitrogen supply. The FL-FIS is a valuable diagnostic tool for
screening site-specific differences in N-availability which is required for precision farming.
Beta vulgaris L.–blue-green fluorescence–chlorophyll fluorescence–fluorescence ratios–nitrogen nutrition–photosynthetic activity–protein–sugars–yield
[show abstract][hide abstract] ABSTRACT: Heavy metal contamination of soils causes serious problems to our society. A small number of interesting plant species have been identified that can grow in soils containing high levels of heavy metals, and can also accumulate these metals to high concentrations in the shoot. The heavy metal contents in root, shoot, leaves and flowers of spontaneous plants grown in metalliferous sites in Albania together with the elemental composition of the native soils were determined by X-ray fluorescence spectrometry. Efficiency of photosynthetic apparatus of analyzed ecotypes was evaluated via chlorophyll fluorescence imaging during induction kinetics. Response of plant root system to the presence of metals, the available pools of metals to plants, effect of plant biomass to phytoextraction, photosynthetic pigment metabolism and chlorophyll fluorescence signature of leaves allowed to characterize hyperaccumulator properties and to detect the variation between selected ecotypes to heavy metal accumulation.
[show abstract][hide abstract] ABSTRACT: 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 micromol 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 micromol 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.
Photosynthesis Research 01/2007; 93(1-3):235-44. · 3.15 Impact Factor
[show abstract][hide abstract] ABSTRACT: It is shown that with a new flash-lamp chlorophyll (Chl) fluorescence imaging system (FL-FIS), the photosynthetic activity of several thousand points of an intact attached leaf can be screened in a non-destructive way within a few seconds. The method allows the detection of the gradients in photosynthetic capacity over different parts of the leaf. The photosynthetic activity is sensed via imaging the Chl fluorescence at its maximum Fm and at steady state Chl fluorescence Fs of the induction kinetics and by the subsequent determination of the image of the fluorescence decrease ratio (RFd) which is known as the vitality index of the photosynthetic apparatus. Under water stress the photosynthetic activity decreases as seen in the images of the two fluorescence ratios RFd and Fm/Fs. Histogram and profile analysis of Chl fluorescence images and Chl fluorescence ratios allow the quantification of the differences between normal and stressed leaves with a high statistical significance.
[show abstract][hide abstract] ABSTRACT: During the greening of etiolated barley seedlings the accumulation of chlorophylls and carotenoids wasdetermined in primary leaves together with the chlorophyll fluorescence ratio F690/F735 (at maximum and steady-state fluorescence) as well as the variable fluorescence decrease ratio (Rfd-values in 690 nm and 735 nm) as calculated from the fluorescence induction kinetics recorded by the LITWaF fluorometer. The variable chlorophyll fluorescence parameters (Fv/Fm, Fv/Fo, ΔF/Fm') were monitored using the pulse amplitude modulation chlorophyll fluorometer PAM, and photosynthetic net CO2 fixation by using a CO2/H2O porometer. All parameters were used to characterize the development of photosynthetic activity under illumination with continuous white light in the upper (oldest), middle and lower (youngest) part of the primary leaf blade of etiolated barley seedlings. The time course of changes in the studied parameters provided information on the gradual and age-dependent development of photosynthetic activity in the three leaf parts of different age. During the greening process the chlorophyll fluorescence ratio F690/F735 at maximum and steady-state fluorescence, fm and fs, strongly correlated with the total chlorophyll content (in an inverse curvilinear relationship) in the upper, middle and lower part of etiolated leaves. Though the absolute values were different, there also existed a linear correlation between the Rfd-values measured at 690 nm and 735 nm.
The time dependence of the variable fluorescence parameters Fv/Fm, Fv/Fo, ΔF/Fm' yielded a saturationcurve, with maximum values at about 12 h of illumination. These variable fluorescence ratios characterized the changes of the efficiency of exciton capture by open PSII reaction centres and the quantum yield of non-cyclic electron transport during the greening of etiolated barley seedlings in the different parts of primary leaves. Fv/Fo exhibited a curvilinear relationship to Fv/Fm and ΔFv/Fm', but a linear relationship to Rfd-values measured at 690 nm and 735 nm during the greening period. Fv/Fo and Rfd-values represent a similar pair of variable fluorescence ratios at the dark-adapted (state 1) and the light-adapted state (state 2) of the photosynthetic apparatus as the ratios Fv/Fm and ΔF/Fm'.
The variation of net CO2 fixation in the middle pan of the leaf blade demonstrated that during the first6 h of greening the net CO2 fixation remained near the zero line, but then rose very fast. In contrast, the variable chlorophyll fluorescence parameters had reached already after 6 h illumination 90 % (Fv/Fm), 88% (ΔF/Fm'), 77% (Fv/Fo) and 60 to 77% (Rfd values at 690 and 735 nm, respectively) of the maximum value. A saturation level of these variable fluorescence ratios was obtained at or around an illumination time of 12 h. These results indicated that the photosynthetic quantum conversion and electron transport within the leaf proceeded at closed stomata and much earlier than measurable C02 fixation, apparently using internal respiratory C02 for photosynthesis. The greening process and development of photosynthetic quantum conversion was faster in the lower and the middle leaf blade parts, but was very much retarded in the upper, oldest part of the leaf blade.
[show abstract][hide abstract] ABSTRACT: This chapter deals with pigment composition, activity and chlorophyll (Chi) fluorescence signatures of the photosynthetic
apparatus as modified by light adaptation, stress events and autumnal senescence. It starts with a description of the regular
pigment composition and function of the different photosynthetic pigments (Chls a and b and several carotenoids) in the chloroplasts. Light adaptations of the photosynthetic apparatus with differential pigment
composition, Chi fluorescence and higher C02 assimilation rates of sun-type and high-light chloroplasts as compared to shade-type and low-light chloroplasts are contrasted.
The Chi fluorescence decrease ratio (RFd) as non-destructive indicator of the C02-fixation rates (PN ) and as vitality index of the photosynthetic apparatus is presented. The RFd values are determined from the Chi fluorescence induction kinetics. They are defined as ratio of the Chi fluorescence decrease
Fd to the steady state Chi fluorescence Fs after onset of photosynthesis: RFd = Fd/Fs = (Fm- Fs)/Fs. Possible modifications in pigment composition and photosynthetic activity (changes in RFd values and PN rates) during the vegetation period and stress events are indicated.
The pigment breakdown, paralleled by measurements of Chi fluorescence parameters, during autumnal senescence is characterized
by a differential breakdown of Chi a and b and of total carotenoids, xanthophylls (x) and carotenes (c). Despite an extensive breakdown of pigments, the Chi fluorescence
decrease ratio, RFd ‘normal’, indicates that the remaining Chi of leaves is photosynthetically active during the major part of the autumnal senescence
process. We emphasize the highly flexible reactivity of the photosynthetic apparatus and show that certain pigment ratios
[Chi a/b and (a + b)/(x + c)] as well as Chi fluorescence parameters (RFd-values) are good indicators of ongoing stress and senescence processes. Finally, the great advantage of the recently developed
Chi fluorescence imaging techniques of leaves, as an excellent means for screening changes in the functionality of the photosynthetic
apparatus during adaptation and stress events, is briefly discussed. Fluorescence imaging of leaves with video Charge Coupled
Device (CCD) cameras, that simultaneously provides the Chi fluorescence information of more than 100,000 leaf pixels, is much
superior to the data on Chi fluorescence measurements applied thus far using conventional fiuorometers which yield average
fluorescence information of only one leaf area point per measurement.
[show abstract][hide abstract] ABSTRACT: In greening barley seedlings the chlorophyll fluorescence emmission spectra were recorded by the Karlsruhe CCD-OMA spectrofluorometer during the fast rise (fast component of Kautsky effect) and the slow decline (slow component of Kautsky effect) of the chlorophyll fluorescence kinetics. The relationships between fluorescence signatures and photosynthetic pigments were used to characterize the development of photosynthetic activity in 7d old etiolated barley seedlings during illumination with continuous white light, The shape of the chlorophyll fluorescence spectra exhibited characteristic changes during the greening of etiolated barley seedlings. At the onset of greening and a very low chlorophyll content only one fluorescence peak near 690 nm was detectable, whereas the second fluorescence peak near 735 nm, initially expressed only as a shoulder, was developed during the chlorophyll accumulation to a separate fluorescence maximum. The time course of the fluorescence intensity near 690 nm and 735 nm at maximum (fm) and steady-state of the chlorophyll fluorescence (fs) can be explained on the basis of a partial reabsorption of the emitted red chlorophyll fluorescence band F690 by the leaf chlorophyll. The chlorophyll fluorescence ratios F690/F735 at fm and fs were determined from the CCD-OMA spectra. The decreasing of the chlorophyll fluorescence ratio F690/F735 with increasing chlorophyll content during greening of the etiolated barley leaves can be expressed by a power function (curvilinear relationship): y=ax-b. The variable chlorophyll fluorescence decrease ratios (Rfd-values) as vitality index were calculated from the fluorescence intensities measured at 690 nm and 735 nm of the CCD fluorescence spectra. The Rdf690 and Rfd735 values increased during greening and exhibited the characteristics of a saturation curve. The latter was reached for Rfd690 after 24 h of illumination (chlorophyll content 14 μm-2) and for Rfd735 already after 6h of illumination (chlorophyll content 8 μ cm-2). The Karlsruhe CCD-OMA spectrofluorometer is excellently suited for photosynthetic studies as well as stress detection in plants.