| Autor: |
Carlos L. Ballaré, T. Mori, Osvaldo E. Sala, Martyn M. Caldwell, Ana L. Scopel, Carla Valeria Giordano |
| Rok vydání: |
2003 |
| Předmět: |
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| Zdroj: |
Plant, Cell & Environment. 26:2027-2036 |
| ISSN: |
0140-7791 |
| DOI: |
10.1046/j.0016-8025.2003.01120.x |
| Popis: |
The ecosystems of Tierra del Fuego (in southern Patagonia, Argentina) are seasonally exposed to elevated levels of ultraviolet-B radiation (UV-B: 280‐315 nm), due to the passage of the ‘ozone hole’ over this region. In the experiments reported in this article the effects of solar UV-B and UV-A (315‐400 nm) on two UV-B defence-related processes: the accumulation of protective UV-absorbing compounds and DNA repair, were tested. It was found that the accumulation of UV-absorbing sunscreens in Gunnera magellanica leaves was not affected by plant exposure to ambient UV radiation. Photorepair was the predominant mechanism of cyclobutane-pyrimidine dimer (CPD) removal in G. magellanica . Plants exposed to solar UV had higher CPD repair capacity under optimal conditions of temperature (25 ° ° ° C) than plants grown under attenuated UV. There was no measurable repair at 8 ° C. The rates of CPD repair in G. magellanica plants were modest in comparison with other species and, under equivalent conditions, were about 50% lower than the repair rates of Arabidopsis thaliana (L er ecotype). Collectively our results suggest that the susceptibility of G. magellanica plants to current ambient levels of solar UV-B in southern Patagonia may be related to a low DNA repair capacity. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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