DNA damage and photosynthesis in Antarctic and Arctic Sanionia uncinata (Hedw.) Loeske under ambient and enhanced levels of UV-B radiation

• Main Authors: Lud, D, Moerdijk, T.C W, van de Poll, W.H., Buma, A.G.J., Huiskes, A.H L
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2002
• Subjects: Sanionia uncinata; Drepanocladus uncinatus; Antarctica; bryophyte; chlorophyll; chlorophyll fluorescence; cyclobutyl pyrimidine dimers; DNA damage; photosynthesis; thymine dimers; UV-B radiation; UV-B supplementation; TIERRA-DEL-FUEGO; STRATOSPHERIC OZONE DEPLETION; ULTRAVIOLET-RADIATION; ATMOSPHERIC CHEMISTRY; MARINE-PHYTOPLANKTON; SOUTHERN ARGENTINA; EARTHS SURFACE; FIELD; PLANTS; Antarctic; Arctic; Argentina; The Antarctic; Antarc*; Phytoplankton; Tierra del Fuego
• Online Access: https://hdl.handle.net/11370/86c60cc9-ce3b-4210-93b1-2168d5b376d3; https://research.rug.nl/en/publications/86c60cc9-ce3b-4210-93b1-2168d5b376d3

The response of the bipolar moss Sanionia uncinata (Hedw.) Loeske to ambient and enhanced UV-B radiation was investigated at an Antarctic (Leonie Island, 67degrees35' S, 68degrees20' W) and an Arctic (Ny-Alesund, 78degrees55' N, 11degrees56' E) site, which differed in ambient UV-B radiation (UV-BR: 280-320 nm) levels. The UV-BR effects on DNA damage and photosynthesis were investigated in two types of outdoor experiments. First of all, sections of turf of S. uncinata were collected in an Arctic and Antarctic field site and exposed outdoors to ambient and enhanced UV-BR for 2 d using UV-B Mini-lamps. During these experiments, chlorophyll a fluorescence, chlorophyll concentration and cyclobutyl pyrimidine dimer (CPD) formation were measured. Secondly, at the Antarctic site, a long-term filter experiment was conducted to study the effect of ambient UV-BR on growth and biomass production. Additionally, sections of moss turf collected at both the Antarctic and the Arctic site were exposed to UV-BR in a growth chamber to study induction and repair of CPDs under controlled conditions. At the Antarctic site, a summer midday maximum of 2.1 W m(-2) of UV-BR did not significantly affect effective quantum yield (F/Fm) and the ratio of variable to maximal fluorescence (Fv/Fm). The same was found for samples of S. uncinata exposed at the Arctic site, where summer midday maxima of UV-BR were about 50% lower than at the Antarctic site. Exposure to natural UV-BR in summer did not increase CPD values significantly at both sites. Although the photosynthetic activity remained largely unaffected by UV-B enhancement, DNA damage clearly increased as a result of UV-B enhancement at both sites. However, DNA damage induced during the day by UV-B enhancement was repaired overnight at both sites. Results from the long-term filter experiment at the Antarctic site indicated that branching of S. uncinata was reduced by reduction of ambient summer levels of UV-BR, whereas biomass production was not affected. Exposure of specimens collected ...