Geosiphon

Geosiphon is a genus of the phylum Glomeromycota, Order Archaeosporales, Family Geosiphonaceae.

Additional recommended knowledge

Essential Laboratory Skills Guide

Don't let static charges disrupt your weighing accuracy

Daily Sensitivity Test

Life cycle

Geosiphon pyriformis is known for being the symbiont of Nostoc. The Geosiphon-Nostoc symbiosis, as by modern definitions, is not a lichen, since it is an intracellular association. Also by functional and evolutionary implications it is more comparable to the arbuscular mycorrhiza symbioses, then to lichens!

The Geosiphon-Nostoc symbiosis is the only known fungal endosymbiosis with cyanobacteria and is characterised by a "siphonal bladder" that is made of a swollen fungal hypha, 0.5-2 mm in size and growing on the soil surface. The upper 2/3 of the "bladder" contains the Nostoc filaments and Nostoc heterocysts, the lower 1/3 is filled with lipid droplets.

Reproduction

The fungal spores are 250 micrometres in diameter, formed at the end of one hypha, or intercalarly (within a hyphae) and resemble those of members of the Glomeromycota.

Somatic structure

Geosiphon has a specialised bladder used to harbour cyanobacteria. Geosiphon pyriformis is not known to form arbuscular mycorrhiza.

References

http://www.geosiphon.de http://www.amf-phylogeny.com

• C.J. Alexopolous, Charles W. Mims, M. Blackwell, Introductory Mycology, 4^th ed. (John Wiley and Sons, Hoboken NJ, 2004) ISBN 0-471-52229-5