Regulation of nitrogenase activity in Bradyrhizobium japonicum/soybean symbiosis by plant N status as determined by shoot C:N ration

azote bradyrhizobium japonicum carbohidratos carbohydrates fixation de l'azote glucide glycine max nitrate nitrates nitratos nitrogen nitrogen fixation nitrogenasa nitrogenase nudosidades radiculares relaciones fuente sumidero relation source puits root nodules simbiosis source sink relations symbiose symbiosis