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Reconciling the incompatible: N 2 fixation And O 2
Author(s) -
Gallon J. R.
Publication year - 1992
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1992.tb00087.x
Subject(s) - nitrogenase , diazotroph , cyanobacteria , limiting , nitrogen fixation , fixation (population genetics) , biology , bacteria , botany , biochemistry , genetics , mechanical engineering , gene , engineering
summary N 2 fixation is an extremely O 2 ‐sensitive process. N 2 ‐fixing bacteria (diazotrophys) have therefore evolved a variety of strategies by which they maintain an active nitrogenase in the presence of atmospheric O 2 and, in some cases, of O 2 generated photosynthetically. In this review, the effects of O 2 on nitrogenase activity and synthesis are described, as are the mechanisms by which diazotrophs limit O 2 damage to nitrogenase. These mechanisms are classified as behavioural strategies, physical barriers or physiological and biochemical strategies. Individual diazotrophs frequently empoly a combination of these. In addition, the particular problems faced by the O 2 ‐evolving cyanobacteria are discussed.CONTENTSSummary 571 I. Introduction 571 II. N 2 fixation 571 III. O 2 toxicity 574 IV. Interrelations between O 2 and N 2 fixation 577 V. Strategies for limiting O 2 damage to nitrogenase 581Acknowledgements 601References 602