Bacterial dinitrogen fixation in the leaf of the northern pitcher plant (Sarracenia purpurea)

Bacterial (Azotobacteriaceae) nitrogenase activity in the leaf cavity of the insectivorous northern pitcher plant (Sarracenia purpurea L.) was assessed by acetylene reduction assay. Results indicated that bacterial dinitrogen fixation occurs in the leaf cavity under normal physiological conditions. This may represent a previously unidentified source of nitrogen for the pitcher plant, as the level of nitrogenase activity measured was sufficient to provide the plant with nitrogen well in excess of that required.