[1] Univ Zurich, Zurich Basel Plant Sci Ctr, Inst Plant Biol, CH-8008 Zurich, Switzerland
[2] Univ Bern, Inst Plant Sci, CH-3013 Bern, Switzerland
[3] Ruhr Univ Bochum, Inst Plant Physiol, D-44801 Bochum, Germany
[4] Univ Florence, Dept Hort, I-50019 Sesto Fiorentino, Italy