Energy State and Dinitrogen Fixation in Soybean Nodules of Dark-grown Plants.

Dark treatment of 25-day-old greenhouse-grown plants of inoculated soybean (Glycine max var. Chippewa) for 1 day reduced ATP by 70%, sucrose by 60%, total adenosine phosphates by 60%, ATP/ADP ratio by 55%, nitrogenase activity by 50%, and energy charge by 15% in nodules. The close correlation between nitrogenase activity and these energy parameters indicates that they may play a major role in regulating dinitrogen fixation in the symbiotic system.