@ARTICLE{Barták_Miloš_Photosynthetic_2012, author={Barták, Miloš and Váczi Peter and Hájek, Josef}, number={No 4}, journal={Polish Polar Research}, pages={443-462}, howpublished={online}, year={2012}, publisher={Polish Academy of Sciences}, publisher={Committee on Polar Research}, abstract={Diurnal measurements of photosynthetic pr ocesses, effective quantum yield of photosystem II ( F PSII ), photosynthetic electron transport rate (ETR) were done in three domi− nant species of Arctic tundra ( Silene acaulis , Dryas octopetala , Salix polaris ) in Petunia− bukta, Spitsbergen. Daily courses of net photosynthesis (P N ) were calculated from chloro− phyll fluorescence data and daily photosynthesi s evaluated. The short−term field measure− ments were carried out in summer 2009, and 2010. Fluorometric parameters ( F PSII and ETR) were measured each 5 minutes as well as microc limate characteristics of the site for 10 (2009) and 8 days (2010), respectively. In all species photosynthetic ETR was well related to incident photosynthetically active radiation a nd leaf temperature. In general, D. octopetala exhibited slightly lower ETR than the other two speci es. Estimated maximu m photosynthetic rate (P Nmax ) reached 17.6, 21.4, and 22.9 μmol CO 2 m −2 s −1 for S. polaris , S. acaulis ,and D. octopetala , respectively. Daily photosynthesis reach ed comparable values in all species, D. otopetala , however, exhibited slightly lower values than the other two species both for overcast and fully sunny days (3.9 and 13.4 mmol CO 2 m −2 d −1 , respectively). The range of daily photosynthesis for S. polaris and S. acaulis studied, reached the ranges of 4.6–6.9 and 14.6–15.2 mmol CO 2 m −2 d −1 for overcast and fully sunny day, respectively.}, type={Artykuły / Articles}, title={Photosynthetic activity in three vascular species of Spitsbergen vegetation during summer season in response to microclimate}, URL={http://ochroma.man.poznan.pl/Content/99537/PDF/v10183-012-0018-z.pdf}, doi={10.2478/v10183−012−0018−z}, keywords={Arctic, Svalbard, vascular plants, plant ecophysiology, net photosynthesis, chlorophyll fluorescence}, }