Lichens to Gunnera, with emphasis on Azolla

N₂-fixing cyanobacteria occur in symbiotic associations with fungi (ascomycetes) as lichens and with a few green plants. The associated cyanobacterium is always a species of Nostoc or Anabaena. Only a small number of plant genera are involved but there is a remarkable range of host diversity. Associ...

Full description

Saved in:

Bibliographic Details
Published in:	Plant and Soil. 1986 Vol. 90; no. 1/3; pp. 17 - 34
Main Authors:	Peters, G.A, Toia, R.E. Jr, Calvert, H.E, Marsh, B.H
Format:	Journal Article Conference Proceeding
Language:	English
Published:	Martius Nijhoff Publishers 01-01-1986
Subjects:	Anabaena Azolla Cyanobacteria Endosymbionts Gunnera Lichens Nitrogen Nitrogen fixation Plants Rice Session 1: Biology of interactions between plants and diazotrophic bacteria Sporophytes Symbionts Symbiosis
Online Access:	Get full text
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	N₂-fixing cyanobacteria occur in symbiotic associations with fungi (ascomycetes) as lichens and with a few green plants. The associated cyanobacterium is always a species of Nostoc or Anabaena. Only a small number of plant genera are involved but there is a remarkable range of host diversity. Associations occur with several bryophytes (e.g. Anthoceros, Blasia, Cavicularia), a pteridophyte (Azolla), cycads (nine genera including Macrozamia and Encephalartos) and an angiosperm (Gunnera). Except for Gunnera, where the cyanobacterium penetrates the plant cells, the cyanobacteria are extracellular with specialized morphological modifications and/or structures of the host plant organs providing an environment which facilitates interaction with the prokaryote. Salient aspects of current knowledge pertaining to the establishment, perpetuation, and functioning of the individual symbioses are summarized. Where possible this includes information concerning recognition and specificity, mode(s) of infection, morphological modifications/adaptations of the host plant and a synopsis of morphological, physiological and biochemical changes common to the symbiotic cyanobacteria. The latter encompasses heterocyst frequencies, enzymes involved in ammonia assimilation, photosynthetic capability and metabolic interaction with the host. The Azolla-Anabaena symbioses, which have potential agronomic significance as an alternative nitrogen source and maintain continuity with the endophyte through the sexual cycle, are emphasized.
Bibliography:	SourceType-Books-1 ObjectType-Book-1 content type line 25 ObjectType-Conference-2 SourceType-Conference Papers & Proceedings-2
ISBN:	9024732832 9789024732838
ISSN:	0032-079X 1573-5036
DOI:	10.1007/BF02277384