1. Biochemistry and Physiology of Plants, Faculty of Biology-W5, Bielefeld University, 33501 Bielefeld, Germany, Biophysical Chemistry, Faculty of Chemistry-F3, Bielefeld University, D-33501 Bielefeld, Germany, and Department of Biochemistry and Cellular and Molecular Biology of Plants, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, E-18008 Granada, Spain