In search of the mechanism of nitrate inhibition of nitrogenase activity in legume nodules: Recent developments

The mechanisms involved in the inhibition of nitrogenase activity in legume nodules by nitrate is unclear. This paper reviews and evaluates proposed mechanisms of this inhibition. Emphasis is placed on recent developments, which suggest that nitrate causes an O 2 limitation of nitrogenase activity. Several mechanisms that involve a nitrate‐induced increase in resistance to O 3 diffusion in the nodule cortex are discussed.