Biological Fixation of Nitrogen for Ecology and Sustainable Agriculture Edited by Andrzej Legocki Polish Academy of Sciences Institute of Bioorganic Chemistry Noskowskiego 12/14 PL-61-704 Poznan, Poland Hermann Bothe Universitat zu Koln, Botanisches Institut GyrhofstraBe 15 D-50923 Koln, Germany Alfred Puhler Universitat Bielefeld Lehrstuhl fur Genetik Postfach 8640 D-35501 Bielefeld, Germany \ With 53 Figures (1 colour plate) and 28 Tables Springer