Origins of non‐linear and dissimilar relationships between epidermal UV absorbance and UV absorbance of extracted phenolics in leaves of grapevine and barley

Kolb, Christiane A.; Pfündel, Erhard

doi:10.1111/j.1365-3040.2005.01302.x

Cited by 97 publications

(37 citation statements)

References 59 publications

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“…The UVA-PAM provides non-destructive estimates of epidermal UV-A transmittance through fluorescence yields of chlorophyll induced by UV-A (375 nm) and blue (470 nm) radiation pulses (Kolb and Pfündel, 2005). Fluorescence induced by UV-A (F UV ) from the mesophyll is compared to fluorescence induced by blue light (F BL ).…”

Section: Uv-a Epidermal Transmittance Measurementsmentioning

confidence: 99%

Solar UV-B Radiation and Global Dimming: Effects on Plant Growth and UV-Shielding

Ryel

Flint

Barnes

2010

UV Radiation in Global Climate Change

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Atmospheric aerosols and other particulates have been linked to reductions in shortwave radiation (global dimming). While much research has focused on the effects on plants caused by ambient and elevated UV-B (290 nm 320 nm), the direct effects of global dimming, and those mediated by associated changes in UV-B radiation, have not been effectively assessed. We conducted an experiment in the high-UV environment of Mauna Kea, Hawaii to compare the effects of UV-B reduction with a simulation of global dimming (accomplished with 13% shading). Using fava beans, (Vicia faba), we found that structural differences due to the treatments were minimal in this high light environment. Most surprising was the minimal effect of UV-B on plant growth given the high UV-B environment. However, both UV-B and shading significantly influenced epidermal UV transmittance, suggesting that changes that occur in secondary chemistry can affect epidermal transmittance for UV. Additional experiments suggest that the change in epidermal transmittance due to shading would most likely occur with foliage in highshade environments. Such changes in secondary chemistry have the potential to affect herbivory, nutrient cycling, and plant response to pathogens. While there are few experimental studies that specifically address possible reductions in radiation due to global dimming, many UV reduction experiments have been conducted in recent decades. Attempts to generalize latitudinal responses from these studies, however, are frustrated by a number of factors. Chief among them are different methodologies (reduction of different UV wavebands in different experiments) and a lack of reporting UV irradiance levels.

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Section: Uv-a Epidermal Transmittance Measurementsmentioning

confidence: 99%

Solar UV-B Radiation and Global Dimming: Effects on Plant Growth and UV-Shielding

Ryel

Flint

Barnes

2010

UV Radiation in Global Climate Change

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“…The efficacy of UV screening in vivo cannot be assessed simply from UV absorbance of extracted phenolics (Liakoura et al 2003, Kolb andPfündel 2005). Therefore, determining epidermal screening needs more direct methods such as absorbance spectrometry on isolated epidermal strips (Grammatikopoulos et al 1999, Markstädter et al 2001, radiometry inside the leaf using micro fibre optics (Bornman and Vogelmann 1988, Day et al 1992, Cen und Bornman 1993, or UV fluorimetry with intact leaves to measure chlorophyll (Chl) fluorescence elicited by UV radiation from which the UV transmittance of the epidermal layer can be derived (Bilger et al 1997, Barnes et al 2000, Burchard et al 2000, Mazza et al 2000.…”

Section: Introductionmentioning

confidence: 99%

UV-A screening in plants determined using a new portable fluorimeter

Kolb¹,

Schreiber²,

Gademann³

et al. 2005

Photosynt.

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UV screening by plant surfaces can be determined by exposing plant organs to UV radiation and measuring the chlorophyll (Chl) fluorescence elicited. From this fluorescence, the UV transmittance can be derived: the more intense the screening the lower the reporter Chl fluorescence and the lower the UV transmittance. The relationships between UV screening at 375 nm, as determined in the field by a portable UV-A-PAM fluorimeter, and UV screening at 314 and 360 nm, measured in the laboratory with the non-portable XE-PAM fluorimeter, were investigated in leaves of grapevine (Vitis vinifera L. cv. Bacchus) and barley (Hordeum vulgare cv. Ricarda), as well as in white grape berries. With leaves, linear trends were observed between XE-PAM measurements at 314 nm and UV-A-PAM measurements at 375 nm but the relationship between transmittance at 360 and 375 nm in barley was curved: a simple model calculation suggests that this curvi-linearity arises from particularly weak absorbance of barley flavonoids at 375 nm relative to absorbance at 360 nm. Transmittance values at 314 nm plotted against 375 nm yielded a much smaller slope in grapevine leaves than in barley leaves, which was attributed to screening in the short-wavelength UV by hydroxycinnamic acids in the former but not in the latter species. With grape berries, a poor correlation was detected between transmittances at 314 and 375 nm which might arise from high scattering of UV radiation at the berry surface. Such artefacts appear to be confined to the UV-B region, as berry transmittance at 360 nm correlated very well with that at 375 nm. Thus, assessment of UV screening in the field at short UV wavelengths using 375 nm readings from a UV-A-PAM fluorimeter is possible provided that information is available on the relationship between the transmittance at the UV wavelength of interest and at 375 nm for the sample tissue being investigated.

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“…The bulk of the phenolics accumulated under high-sunlight stress are situated within a superficial protective complex comprising cuticle, epidermis, and several underlying cell layers (see Chap. 2;Bornman 1999;Kolb and Pfundel 2005;Solovchenko and Merzlyak 2003;Solovchenko and Schmitz-Eiberger 2003). According to measurements carried out on preparations (Baur et al 1998;Krauss et al 1997;Solovchenko and Merzlyak 2003), plant cuticles do not exhibit measurable absorption in the near-IR and visible parts of the spectrum and transmit nonreflected PAR nearly completely (80-98% of incident radiation), reflecting, on average, 15-17% (Fig.…”

Section: Selective Screening Of Par and Uv Radiation By Cuticle And Ementioning

confidence: 98%

Manifestations of the Buildup of Screening Pigments in the Optical Properties of Plants

Solovchenko

2010

Springer Series in Biophysics

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Accumulation of screening pigments manifests itself as directional changes in plant optical properties. Understanding the relationships between the magnitude and spectral quality of these changes and the extent of the underlying buildup of screening pigments could provide valuable insights into the status of screening-related photoprotection in plants. This chapter focuses on manifestations of the induction of screening pigments in reflectance and absorption spectra of microalgae and plants and lays a foundation for nondestructive quantification of screening compounds and their efficiency in plants.Plant cells and tissues comprising many components and structures of different morphology, chemical composition, and physical properties (such as refraction index) and containing high amounts of pigments are intricate, inhomogeneous optical systems (Butler and Norris 1960;Fukshansky 1981;Oborne and Raven 1986;Ustin et al. 2001;Vogelmann 1993). The efficiency of light absorption by both photoprotective pigments depends to a considerable extent, apart from their content, on a number of other factors exerting profound effects on the pigment spectra in planta (Butler and Norris 1960;Gonnet 1999Gonnet , 2003Smith and Markham 1998). For example, more than a half of the variation of light absorption by chlorophyll a in the cells of the green microalga Dunaliella tertiolecta in the course of its acclimation to irradiation intensity is explained by changes in the degree of thylakoid membrane stacking and less than a half is explained by changes in chlorophyll content per se (Berner et al. 1989).Numerous studies (see, e.g., Merzlyak et al. 2005aMerzlyak et al. , b, 2008a Merzlyak 2003, 2008) showed that the rearrangements of the plant pigment apparatus, including buildup of screening pigments during adaptation to illumination conditions, inevitably manifests itself in plant optical properties. Accordingly, the analysis of reflectance and absorption spectra of algae and plants provides valuable

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Origins of non‐linear and dissimilar relationships between epidermal UV absorbance and UV absorbance of extracted phenolics in leaves of grapevine and barley

Cited by 97 publications

References 59 publications

Solar UV-B Radiation and Global Dimming: Effects on Plant Growth and UV-Shielding

Solar UV-B Radiation and Global Dimming: Effects on Plant Growth and UV-Shielding

UV-A screening in plants determined using a new portable fluorimeter

Manifestations of the Buildup of Screening Pigments in the Optical Properties of Plants

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