Comparison of peas nodulated with a hydrogen-uptake positive or negative Strain ofRhizobium leguminosarum

During a 49-d growth period peas nodulated with a Hup⁺ strain ofR. leguminosarum (17-to 66-d-old plants) had a significantly higher total (by 80 %) and specific (by 155 %) C₂H₂-reducing nitrogenase activity a lower dihydrogen production by the root nodules (by 53 %), and a higher value of the relative efficiency coefficient of nitrogen fixation (by 45 %) in comparison with the plants nodulated with a Hup^- strain. The nodules induced by the Hup⁺ strain evolved less CO₂ per unit of the acetylene-reducing activity than those induced by the Hup^- strain (by 30 %). However, the accumulation of the nodule dry mass was significantly lower in the plants nodulated with the Hup⁺ strain.