Effects of Reducing the Ambient UV-B Radiation in the High Arctic on Salix arctica and Vaccinium uliginosum.

• Main Authors: Albert, Kristian, Ro-Poulsen, Helge, Mikkelsen, Teis Nørgaard, Bredahl, L., Haakansson, K.B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2005
• Subjects: Arctic; Greenland; East Greenland
• Online Access: https://curis.ku.dk/portal/da/publications/effects-of-reducing-the-ambient-uvb-radiation-in-the-high-arctic-on-salix-arctica-and-vaccinium-uliginosum(1bf1d580-74c3-11db-bee9-02004c4f4f50).html; https://curis.ku.dk/ws/files/5466889/paper_Albert2005_phyton.pdf

Udgivelsesdato: 1 October 2005 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 ¿ > 320 nm, and Lexan, transmitting ¿ > 400 nm) were used to reduce UV-B radiation and UV-B+A respectively. A UV transparent film (Teflon, transmitting ¿ > 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 (F v/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.