Effects of ultraviolet radiation on aquatic bryophytes
The depletion of the stratospheric ozone layer as a result of anthropogenic activities increases the ultraviolet-B (UV-B) irradiance at ground level. This may lead to harmful biological consequences affecting photosynthetic organisms. Mountain streams are especially exposed to a UV-B increase, and b...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2006 |
| País: | España |
| Institución: | Universitat Autònoma de Barcelona |
| Repositorio: | Dipòsit Digital de Documents de la UAB |
| Idioma: | inglés |
| OAI Identifier: | oai:ddd.uab.cat:26681 |
| Acceso en línea: | https://ddd.uab.cat/record/26681 |
| Access Level: | acceso abierto |
| Palabra clave: | Briòfits aquàtics Molsa Radiació ultravioleta-B (UV-B) Rierols de muntanya Bioindicadors Hepàtiques Briófitos acuáticos Musgos Hepáticas Radiación ultravioleta-B (UV-B) Arroyos de montaña Bioindicadores Aquatic bryophytes Mosses Liverworts Ultraviolet-B (UV-B) radiation Mountain streams Bio-indicators |
| Sumario: | The depletion of the stratospheric ozone layer as a result of anthropogenic activities increases the ultraviolet-B (UV-B) irradiance at ground level. This may lead to harmful biological consequences affecting photosynthetic organisms. Mountain streams are especially exposed to a UV-B increase, and bryophytes play a key ecological role in them. In this paper, the effects of enhanced UV-B radiation on photosynthetic organisms in general and on bryophytes in particular are described. Hereafter, some results obtained by our group on the effects of UV-B on bryophytes from mountain streams are presented. Laboratory and field experiments show that these effects depend on the species, the environmental factors (such as temperature), and the origin of the samples (sun or shade conditions, low or high altitude). Among the variables measured, the maximum quantum yield of photosystem II (Fv/Fm) and the level of UV-absorbing compounds seem to be the most responsive to enhanced UV-B, but no variable responded in the same manner in every species. The potential use of aquatic bryophytes as bio-indicators of changes in ambient UV-B radiation would require an adequate selection of both variables and species. Promising variables are Fv/Fm, the concentration of UV-absorbing compounds (especially if they are analyzed individually) and DNA damage, whereas the liverwort Jungermannia exsertifolia subsp. cordifolia has been revealed to be a good bio-indicator species. Globally, the responses of aquatic bryophytes to UV-B radiation and their protecting systems are still poorly characterized, and thus further study is required under both controlled and field conditions. |
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