1. Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel 2000, Switzerland
2. Institute of Plant Sciences, University of Bern, Bern 3013, Switzerland
3. Oeschger Centre for Climate Change Research (OCCR), University of Bern, Bern 3012, Switzerland
4. Plant Physiology Unit, The Department of Life Sciences and Systems Biology of the University of Turin, Via Accademia Albertina 13, Torino 10123, Italy
5. Department of Systematic and Evolutionary Botany, University of Zürich, Zürich 8008, Switzerland