Spore germination and hyphal growth of a vesicular–arbuscular mycorrhizal fungus, Glomus mosseae (Gerdemann and Trappe), under decreased oxygen and increased carbon dioxide concentrations

1983 ◽  
Vol 29 (10) ◽  
pp. 1280-1285 ◽  
Author(s):  
F. Le Tacon ◽  
F. A. Skinner ◽  
Barbara Mosse
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Tension ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Glomus Mosseae ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Hyphal Growth ◽  
Low Oxygen ◽  
Vesicular Arbuscular

Spore germination and hyphal growth from spores of the vesicular–arbuscular endophyte Glomus mosseae have been studied under different oxygen and carbon dioxide tensions. Spores failed to germinate at low oxygen tension. This effect was reversible. However, mycelial growth from spores not preincubated in air was irreversibly damaged. The mycelial growth from preincubated spores was affected by oxygen tension. Between 21 and 3% oxygen, growth decreased slightly. Below 3% oxygen it decreased sharply. Again this effect was reversible. A tension of 5% carbon dioxide had no effect on spore germination, but reduced hyphal growth consistently at all oxygen tensions. This effect persisted when spores were subsequently returned to air.

Physiological factors determining vesicular–arbuscular mycorrhizal formation in host and nonhost Ri T-DNA transformed roots

1990 ◽  
Vol 68 (6) ◽  
pp. 1260-1264 ◽  
Author(s):  
G. Bécard ◽  
Y. Piché
Keyword(s):  
Sugar Beet ◽  
Mycorrhizal Fungus ◽  
Arbuscular Mycorrhizal ◽  
Hyphal Growth ◽  
Transformed Roots ◽  
Physiological Factors ◽  
Nonhost Plant ◽  
Mycorrhizal Associations ◽  
Vesicular Arbuscular ◽  
Arbuscular Mycorrhizal Associations

Transformed roots of carrot (Umbelliferae) and sugar beet (Chenopodiaceae) were used as model host and nonhost plant, respectively, for the vesicular–arbuscular mycorrhizal fungus Gigaspora margarita (Becker & Hall). Rapid growth of hyphae from germinating spores of G. margarita and formation of infection units were obtained only in the presence of carrot roots. Root volatiles from both plant species have similar stimulative effects on hyphal growth. However, hyphal growth was stimulated by root exudates of carrot and not by those of sugar beet. These and other results suggest that the nonmycorrhizal roots of sugar beet lack factors that promote mycorrhizal infection rather than producing inhibitory factors. The model used in this study is especially appropriate for further investigations on the recognition mechanisms involved in vesicular–arbuscular mycorrhizal associations.

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