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UV-induced changes in pigment content and light penetration in the fruticose lichen Cladonia arbuscula ssp. mitis

Buffoni Hall, Roberta LU ; Bornman, Janet LU and Björn, Lars Olof LU (2002) In Journal of Photochemistry and Photobiology, B: Biology 66(1). p.13-20
Abstract
The response of the lichen, Cladonia arbuscula (Wallr.) Flot. ssp. mitis (Sandst.) Ruoss to enhanced UV-B (280-315 nm) radiation was investigated with respect to: (a) changes in phenolic content; (b) differential pigment accumulation under visible and UV radiation with increasing distance from thallus apices; and (c) the internal distribution of UV-B radiation within the thallus measured with quartz optical fibres. In a short-term experiment, lichens were exposed for 7 days in a growth chamber to visible light with or without additional UV-B radiation. For a longer term experiment, lichens were grown outdoors under both natural UV radiation, and supplemental UV-A (315–400 nm)+UV-B provided by lamps. Controls were placed under filters that... (More)
The response of the lichen, Cladonia arbuscula (Wallr.) Flot. ssp. mitis (Sandst.) Ruoss to enhanced UV-B (280-315 nm) radiation was investigated with respect to: (a) changes in phenolic content; (b) differential pigment accumulation under visible and UV radiation with increasing distance from thallus apices; and (c) the internal distribution of UV-B radiation within the thallus measured with quartz optical fibres. In a short-term experiment, lichens were exposed for 7 days in a growth chamber to visible light with or without additional UV-B radiation. For a longer term experiment, lichens were grown outdoors under both natural UV radiation, and supplemental UV-A (315–400 nm)+UV-B provided by lamps. Controls were placed under filters that removed the radiation below 290 nm from the natural sunlight. The concentration of total phenolic compounds was measured spectrophotometrically at the termination of the experiments, in different parts of the lichen podetia. UV-exposed lichens showed increased accumulation of phenolics compared to those not grown under UV. At the termination of the long-term experiment, fibre optic measurements of the penetration of radiation into lichen thallus reflected the influence of growth under UV radiation, whereby UV was more strongly attenuated as compared to that in lichens not exposed to enhanced levels of UV-B radiation. Results indicated that in Cladonia, UV-B radiation induces the accumulation of phenolic compounds that may have a protective role. In addition, the morphological distribution of phenolic compounds was different under visible and supplemental UV-B radiation. Internal radiation measurements served to visualise the attenuation of radiation with thallus depth for different wavelengths in the UV-B waveband. (Less)
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type
Contribution to journal
publication status
published
subject
in
Journal of Photochemistry and Photobiology, B: Biology
volume
66
issue
1
pages
13 - 20
publisher
Elsevier
external identifiers
  • wos:000174008300003
  • scopus:0036471698
ISSN
1011-1344
DOI
10.1016/S1011-1344(01)00270-6
project
Photobiology
language
English
LU publication?
yes
id
8662b006-05f6-4de6-82ea-4fae0f234be3 (old id 134381)
date added to LUP
2007-07-30 14:20:22
date last changed
2017-10-22 04:42:16
@article{8662b006-05f6-4de6-82ea-4fae0f234be3,
  abstract     = {The response of the lichen, Cladonia arbuscula (Wallr.) Flot. ssp. mitis (Sandst.) Ruoss to enhanced UV-B (280-315 nm) radiation was investigated with respect to: (a) changes in phenolic content; (b) differential pigment accumulation under visible and UV radiation with increasing distance from thallus apices; and (c) the internal distribution of UV-B radiation within the thallus measured with quartz optical fibres. In a short-term experiment, lichens were exposed for 7 days in a growth chamber to visible light with or without additional UV-B radiation. For a longer term experiment, lichens were grown outdoors under both natural UV radiation, and supplemental UV-A (315–400 nm)+UV-B provided by lamps. Controls were placed under filters that removed the radiation below 290 nm from the natural sunlight. The concentration of total phenolic compounds was measured spectrophotometrically at the termination of the experiments, in different parts of the lichen podetia. UV-exposed lichens showed increased accumulation of phenolics compared to those not grown under UV. At the termination of the long-term experiment, fibre optic measurements of the penetration of radiation into lichen thallus reflected the influence of growth under UV radiation, whereby UV was more strongly attenuated as compared to that in lichens not exposed to enhanced levels of UV-B radiation. Results indicated that in Cladonia, UV-B radiation induces the accumulation of phenolic compounds that may have a protective role. In addition, the morphological distribution of phenolic compounds was different under visible and supplemental UV-B radiation. Internal radiation measurements served to visualise the attenuation of radiation with thallus depth for different wavelengths in the UV-B waveband.},
  author       = {Buffoni Hall, Roberta and Bornman, Janet and Björn, Lars Olof},
  issn         = {1011-1344},
  language     = {eng},
  number       = {1},
  pages        = {13--20},
  publisher    = {Elsevier},
  series       = {Journal of Photochemistry and Photobiology, B: Biology},
  title        = {UV-induced changes in pigment content and light penetration in the fruticose lichen Cladonia arbuscula ssp. mitis},
  url          = {http://dx.doi.org/10.1016/S1011-1344(01)00270-6},
  volume       = {66},
  year         = {2002},
}