Genotypic difference in the short-term response of nitrogenase activity (C2H2 reduction) to salinity and oxygen in the common bean Rachid Serraj, Humberto Vasquez-Diaz, German Hernandez and Jean-Jacques Drevon Agronomie, 21 6-7 (2001) 645-651 DOI: 10.1051/agro:2001156