1. Department of Biological and Environmental Sciences University of Gothenburg Box 461 Gothenburg 405 30 Sweden
2. Department of Biology Texas A&M University 3258 TAMU College Station TX 77843 USA
3. Laboratory for Neutron Scattering and Imaging Paul Scherrer Institute Villigen PSI 5232 Switzerland
4. Institute for Solid State Physics and Optics Wigner Research Centre for Physics Hungarian Academy of Sciences Box 49 Budapest H‐1525 Hungary
5. Institute of Plant Biology Biological Research Centre Hungarian Academy of Sciences Box 521 Szeged H‐6701 Hungary