Interactive effects of high irradiance and moderate heat on photosynthesis, pigments, and tocopherol in the tree-fern Dicksonia antarctica
Liubov Volkova, Michael Tausz, Lauren T Bennett, Erwin Dreyer
Functional Plant Biology: an international journal of plant function | CSIRO PUBLISHING | Published : 2009
Effects of high irradiance and moderate heat on photosynthesis of the tree-fern Dicksonia antarctica (Labill., Dicksoniaceae) were examined in a climate chamber under two contrasting irradiance regimes (900 and 170 µmol photons m-2 s-1) and three sequential temperature treatments (15°C; 35°C; back to 15°C). High irradiance led to decline in predawn quantum yield of photochemistry, Fv/Fm (0.73), maximal Rubisco activity (Vcmax; from 37 to 29 µmol m-2s-1), and electron transport capacity (Jmax; from 115 to 67 µmol m-2 s-1). Temperature increase to 35°C resulted in further decreases in Fv/Fm (0.45) and in chlorophyll bleaching of high irradiance plants, while Vcmax and Jmax were not affected. C..View full abstract
Liubov Volkova acknowledges support by a Melbourne Research Scholarship and by an S. F. Pond Trust Travelling Scholarship for 2006. The work was in part supported by a research contract with the Victorian Department of Sustainability and Environment and by an internal grant of the University of Melbourne to M Tausz. Thanks to Andrew Merchant for useful hints on the experimental design, to all the kind and helpful staff of INRA Nancy, in particular to Christophe Bailly for ensuring smooth operation of the climate chamber during the experiment, Jean Marie Gioria for growing the tree-ferns, and to Jacqueline Marchand for N quanti. cation in the fronds. Damien L. Callahan, School of Botany, University of Melbourne, is personally thanked for help with operating the HPLC.