Effects of reducing the ambient UV-B radiation in the high Arctic on Salix arctica and Vaccinium uliginosum

• Main Authors: Albert, K.R., Ro-Poulsen, H., Mikkelsen, Teis Nørgaard, Bredahl, L., Haakansson, K.B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2005
• Subjects: 9-B risiko; /dk/atira/pure/sustainabledevelopmentgoals/good_health_and_well_being; SDG 3 - Good Health and Well-being; Arctic; Greenland; East Greenland
• Online Access: https://orbit.dtu.dk/en/publications/3c61e2b8-ad5f-41ff-9e9e-1d392b4017bb; https://backend.orbit.dtu.dk/ws/files/4005518/paper_Albert2005_phyton.pdf

Effects of reducing the ambient UV-B radiation on gas exchange and chlorophyll fluores-cence of two dwarf shrub species, Salix arctica and Vaccinium uliginosum, was studied in a high arctic heath in North East Greenland during two growing seasons. Films (Mylar, transmitting λ > 320 nm, and Lexan, transmitting λ > 400 nm) were used to reduce UV-B radiation and UV-B+A respectively. A UV transparent film (Teflon, transmitting λ > 280 nm) and no film were used as controls. Field measurements showed that the plants under Teflon, Mylar and Lexan received app. 91%, 39% and 17% of the ambient UV-B irradiance, respectively. UV radiation decreased the maximal photochemical efficiency (Fv/Fm) and other fast fluorescence transient derived parameters in both species, despite an increased level of leaf flavonoid content. The responses varied in signifi-cance according to species and site. The relation of these effects to a significantly decreased stomatal conductance (gs) and intercellular CO2 concentration (Ci) pointed to respiration as an im-portant factor in the interpretation of the observed unaffected net CO2 assimilation (Pn) in UV- re-duced treatments. It is concluded that the studied species have not fully acclimatized to the level of ambient UV-B radiation, and that ambient UV-B level is an important stress factor for the investi-gated plants in High Arctic.