Title : Plasticity of photosynthetic heat tolerance in plants adapted to thermally contrasting biomes Running head : Plasticity of photosynthetic heat tolerance

Affiliations: ARC Centre of Excellence in Plant Energy Biology, Research School of Biology, Building 134, The Australian National University, Canberra, ACT 2601, Australia. Division of Plant Sciences, Research School of Biology, Building 46, The Australian National University, Canberra, ACT 2601, Australia. Division of Ecology and Evolution, Research School of Biology, Building 116, The Australian National University, Canberra, ACT 2601, Australia. Faculty of Agriculture, University of Peradeniya, Peradeniya, 20400 Sri Lanka *Correspondence to: Owen.Atkin@anu.edu.au, Tel: +61 2 6125 5046, Fax: +61 2 6125 5095