Initial Assessment of Physiological Response to UV-B Irradiation Using Fluorescence Measurements

Middleton, Elizabeth M.; Chappelle, Emmett W.; Cannon, Takisha A.; Adamse, P.; Britz, Steven J.

doi:10.1016/s0176-1617(96)80296-3

Cited by 24 publications

(24 citation statements)

References 39 publications

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“…On the contrary, UV‐induced fluorescence spectra receive the contribution of different fluorophores (various hydroxycinnamic acids and flavonoids), and the relative abundance of different phenolic classes may be estimated by the changes in the spectrum shape, using a single excitation wavelength (55,59). A markedly higher contribution of the green–yellow than the blue band to the tissue fluorescence has been previously reported to occur in whole leaves exposed to various environmental constraints (60) including UV stress (61,62). Our data show that contrasting solar radiation sharply alters the UV‐induced blue–green fluorescence of P. latifolia cross sections and microspectrofluorometry can be a valuable tool to detect environment‐induced changes in secondary metabolism at the intercellular level (Figs.…”

Section: Discussionmentioning

confidence: 95%

Flavonoid Distribution in Tissues of Phillyrea latifolia L. Leaves as Estimated by Microspectrofluorometry and Multispectral Fluorescence Microimaging¶

Agati¹,

Galardi

Gravano

et al. 2007

Photochemistry and Photobiology

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A new method for detecting the tissue‐specific distribution of flavonoids has been developed by coupling microspectrofluorometry and multispectral fluorescence microimaging techniques. Fluorescence responses of cross sections taken from 1 year old Phillyrea latifolia leaves exposed to full (sun leaves) or 15% (shade leaves) solar radiation in a coastal area of Southern Tuscany were analyzed. Fluorescence spectra of different tissue layers, each normalized at its fluorescence maximum, that were stained or not stained with Naturstoff reagent A (in ethanol), under excitation with UV light (λexc= 365 nm) or blue light (λexc= 436 nm) were recorded. The shape of the fluorescence spectra of tissue layers from shade and sun leaves differed only under UV excitation. The fluorescence of stained cross sections from sun and shade leaves as well as from different layers of sun leaves received a markedly different contribution from the blue (470 nm) and the yellow‐red (580 nm) wavebands. Such changes in tissue fluorescence signatures were related to light‐induced changes of extractable caffeic acid derivatives and flavonoid glycosides, namely quercetin 3‐O‐rutinoside and luteolin 7‐O‐glucoside. Wall‐bound phenolics, i.e. hydroxycinnamic acids (p‐coumaric, ferulic and caffeic acid) and flavonoids (apigenin and luteolin derivatives), did not substantially differ between sun and shade leaves. A Gaussian deconvolution analysis of fluorescence spectra was subsequently performed to estimate the contribution of flavonoids (emitting at 600 nm, F600 [red fluorescence contribution = signal integrated over a Gaussian band centered at about 600 nm]) relative to the tissue fluorescence (Ftot [total fluorescence = signal integrated over the whole fluorescence spectrum]). The F600/Ftot ratios sharply differed between analogous tissues of sun and shade leaves, as well as among tissue layers within each leaf type. A highly resolved picture of the tissue flavonoid distribution was finally provided through a fluorescence microimaging technique by acquiring fluorescence images at the blue (fluorescence at about 470 nm [F470]) and yellow‐red (fluorescence at about 580 nm [F580]) wavelengths and correcting the F580 image for the contribution of nonflavonoids to the fluorescence at 580 nm. Monochrome images were elaborated by adequate computing functions to visualize the exclusive accumulation of flavonoids in different layers of P. latifolia leaves. Our data show that in shade leaves flavonoids almost exclusively occurred in the adaxial epidermal layer. In sun leaves flavonoids largely accumulated in the adaxial epidermal and subepidermal cells and followed a steep gradient passing from the adaxial epidermis to the inner spongy layers. Flavonoids also largely occurred in the abaxial epidermal cells and constituted the exclusive class of phenylpropanoids synthesized by the cells of glandular trichomes. The proposed method also allowed for the discrimination of the relative abundance of hydroxycinnamic derivatives and flavonoids in different...

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Section: Discussionmentioning

confidence: 95%

Flavonoid Distribution in Tissues of Phillyrea latifolia L. Leaves as Estimated by Microspectrofluorometry and Multispectral Fluorescence Microimaging¶

Agati¹,

Galardi

Gravano

et al. 2007

Photochemistry and Photobiology

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“…The calculated R derivative (D) indices, suggested as sensitive to stress and to reflect the differences in the shape of the first D curve among damage levels (Entcheva, 2000), included the ratio of the Dmax to D714 and D744 nm (Dmax/D714, Dmax/D744), the Dmax/D705, Dmax/D745, and D715/D705. Previous investigations have identified a large utility of spectral R and F indices related to vegetation physiologic properties (Chappelle et al, 1992; Carter, 1994; Gitelson and Merzlyak, 1996; Middleton et al, 1996; Gamon et al, 1997; Datt, 1998; Merzlyak et al, 1999; Zarco‐Tejada et al, 1999; Entcheva, 2000; Entcheva et al, 2004). The current study evaluated approximately 25 of the previously published R and F parameters to determine those most suitable for separation of environmental stress levels.…”

Section: Methodsmentioning

confidence: 99%

Assessment of Vegetation Stress Using Reflectance or Fluorescence Measurements

et al. 2007

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Current methods for large-scale vegetation monitoring rely on multispectral remote sensing, which has serious limitation for the detection of vegetation stress. To contribute to the establishment of a generalized spectral approach for vegetation stress detection, this study compares the ability of high-spectral-resolution reflectance (R) and fluorescence (F) foliar measurements to detect vegetation changes associated with common environmental factors affecting plant growth and productivity. To obtain a spectral dataset from a broad range of species and stress conditions, plant material from three experiments was examined, including (i) corn, nitrogen (N) deficiency/excess; (ii) soybean, elevated carbon dioxide, and ozone levels; and (iii) red maple, augmented ultraviolet irradiation. Fluorescence and R spectra (400-800 nm) were measured on the same foliar samples in conjunction with photosynthetic pigments, carbon, and N content. For separation of a wide range of treatment levels, hyperspectral (5-10 nm) R indices were superior compared with F or broadband R indices, with the derivative parameters providing optimal results. For the detection of changes in vegetation physiology, hyperspectral indices can provide a significant improvement over broadband indices. The relationship of treatment levels to R was linear, whereas that to F was curvilinear. Using reflectance measurements, it was not possible to identify the unstressed vegetation condition, which was accomplished in all three experiments using F indices. Large-scale monitoring of vegetation condition and the detection of vegetation stress could be improved by using hyperspectral R and F information, a possible strategy for future remote sensing missions.

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“…At the same time, the importance of the Red and FR spectral regions for the assessment of photosynthetic function using chlorophyll fluorescence (ChlF), which produces peaks at 685 and 740 nm, has been well established in laboratory studies [6]. Fluorescence peaks in the blue and green spectra, or ratios to ChlF peaks (e.g., Red/FR and Red/blue fluorescence emission ratios), have also been related to vegetation vigor [7,8,9,10,11,12]. However, the links among ChlF, blue/green emissions, and the red edge optical spectra have not been well studied, nor has the role of nitrogen (N) in influencing the spectral properties of foliage in the red edge.…”

Section: Introductionmentioning

confidence: 99%

Optical and fluorescence properties of corn leaves from different nitrogen regimes

et al. 2003

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The important role of nitrogen (N) in limiting or enhancing vegetation productivity is relatively well understood, although the interaction of N with other environmental variables in natural and agricultural ecosystems needs more study. In 2001, a suite of optical, fluorescence, and biophysical measurements were collected on leaves of corn (Zea Mays L.) from field plots provided four N fertilizer application rates: 20%, 50%, 100% and 150% of optimal N levels. Two complementary sets of high-resolution (< 2 nm) optical spectra were acquired for both adaxial and abaxial leaf surfaces. The first was comprised of leaf optical properties (350-2500 nm) for reflectance, transmittance, and absorptance. The second was comprised of reflectance spectra (500-1000 nm) acquired with and without a long pass 665 nm filter to determine the fluorescence contribution to "apparent reflectance" in the 670-750 nm spectrum that includes the 685 and 740 nm chlorophyll fluorescence (ChlF) peaks. Two types of fluorescence measurements were also made on adaxial and abaxial surfaces: 1) fluorescence images in four 10 nm bands (blue, green, red, far-red) resulting from broadband irradiance excitation; and 2) emission spectra at 5 nm resolution produced by three excitation wavelengths (280, 380, and 532 nm). The strongest relationships between optical properties and foliar chemistry were obtained for a "red-edge" optical parameter versus C/N and chlorophyll b. Select optical indices and ChlF parameters were correlated. A significant contribution of steady-state ChlF to apparent reflectance was observed, averaging 10-25% at 685 nm and 2-6% at 740 nm over the range of N treatments. From all measurements assessing fluorescence, higher ChlF was measured from the abaxial leaf surfaces.Keywords: high spectral resolution reflectance and fluorescence, chlorophyll fluorescence, carbon/nitrogen ratio, chlorophyll b, red edge, nitrogen deficiency and excess.

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Initial Assessment of Physiological Response to UV-B Irradiation Using Fluorescence Measurements

Cited by 24 publications

References 39 publications

Flavonoid Distribution in Tissues of Phillyrea latifolia L. Leaves as Estimated by Microspectrofluorometry and Multispectral Fluorescence Microimaging¶

Flavonoid Distribution in Tissues of Phillyrea latifolia L. Leaves as Estimated by Microspectrofluorometry and Multispectral Fluorescence Microimaging¶

Assessment of Vegetation Stress Using Reflectance or Fluorescence Measurements

Optical and fluorescence properties of corn leaves from different nitrogen regimes

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