1. Laboratory of Plant Physiology, Department of Agricultural Biotechnology, Agricultural University of Athens, Iera Odos 75, Votanikos, 11855 Athens, Greece
2. Stable Isotope Unit, Institute of Material Science, National Center for Scientific Research ‘Demokritos’ 153 10 Aghia Paraskevi, Attiki, Greece
3. School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney NSW 2052, Australia
4. Present address: Faculty of Agriculture, Food and Natural Resources, Institute for Sustainable Solutions, The University of Sydney, NSW 2006, Australia