1. Unit of Plant Molecular Cell Biology, Institute for Biology I, RWTH Aachen University , Worringerweg 1, 52056 Aachen , Germany
2. Department of Experimental Plant Biology, Faculty of Science, Charles University , Viničná 5, 128 44 Prague , Czech Republic
3. Área de Fisiología Vegetal, Departamento de Ingeniería y Ciencias Agrarias, Universidad de León , 24071 León , Spain
4. Institute for Plant Cell Biology and Biotechnology, Heinrich-Heine-University Düsseldorf , Universitätsstr. 1, 40225 Düsseldorf , Germany
5. Institute of Experimental Botany of the Czech Academy of Sciences , Laboratory of Cell Biology, Rozvojová 263, 165 02 Prague 6 Lysolaje , Czech Republic