Nature 265, 371 - 372 (27 January 1977); doi:10.1038/265371a0

Modifications of nitrogen-fixing algae in lichen symbioses

W. D. P. STEWART & P. ROWELL

Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK

THE factors responsible for the establishment of lichen symbioses involving nitrogen-fixing blue-green algae are poorly understood^1,2 and it has not been clear how the algae are modified to remain in association, virtually ceasing to grow and yet fixing N₂ at high rates. We report here that in the lichen genus Peltigera morphological, physiological and biochemical modifications of the algae may all be involved in this process.

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