Glomus tortuosum

N.C. Schenck & G.S. Sm.

SPORES single in the soil or in sporocarps; spores pale yellow (4A3) to light yellow (4A4); globose to subglobose; (140-)180(-240) µm diam; sometimes ovoid; 140-170 x 180-240 µm; with one subtending hypha; most mature both single spores and those arranged in sporocarps are surrounded by a peridium, probably developing from the region of their subtending hypha.
Sporocarps globose, 280-620 µm diam, to irregular, 140-280 x 430-640 µm, with 2-6 randomly distributed spores.

SUBCELLULAR STRUCTURE OF SPORES consists of one wall including one layer (swl).

In PVLG+Melzer's reagent
In PVLG

Layer 1 laminate, pale yellow (4A3) to light yellow (4A4), (1.2-)2.2(-2.6) µm thick, not staining in Melzer's reagent; its laminae frequently separate from each other in crushed spores.

Peridium 8.0-22.0 µm thick; composed of tightly interwoven, straight and branched; septate; hyaline to yellowish white (4A2) hyphae; 2.7-7.8 µm wide; with walls 0.5-1.0 µm thick.

In PVLG
In PVLG+Melzer's reagent

Juvenile and young spores frequently with no peridium.

 

 

SUBTENDING HYPHA pale yellow (4A3) to light yellow (4A4); straight or curved; cylindrical to flared; (11.5-)13.5(-15.0) µm wide at the the spore base, usually covered with the peridium and, thereby, difficult to see.

In PVLG+Melzer's
Wall of subtending hypha pale yellow (4A3) to light yellow (4A4); (1.0-)1.6(-1.9) µm thick at the spore base; composed of one layer, continuous with the spore wall layer.

Pore gradually thins with age due to thickening of the subtending hyphal wall layer; no septum was observed in the spores examined.

 

 

GERMINATION. Not observed.

MYCORRHIZAE. The author of this website did not establish one-species culture of this fungus yet.

DISTRIBUTION. Glomus tortuosum has originally been obtained from around Glycine max (L.) Merr. roots cultivated in Florida (Schenck and Smith 1982). According to Koske (1987), Gl. tortuosum was one of the five most important arbuscular fungi associated with Ammophila breviligulata Fern. and Uniola paniculata L. colonizing barrier dunes extending from northern New Jersey to Virginia. This fungus has also been found in dunes of India and Japan (Sridhar and Beena 2001). Cabello (2001) isolated Gl. tortuosum from the root zone of Cyndon dactylon (L.) Pers. growing in a hydrocarbon-polluled soil located in Ensenada, Buenos Aires province, Argentina, and Oehl et al. (2003) reported its presence in a grassland of Switzerland.

The spores of Gl. tortuosum characterized here were isolated from trap cultures containing root-rhizosphere soil mixtures taken from under A. breviligulata growing in maritime dunes of New Jersey, U.S.A.

NOTES. The most distinctive characters of Gl. tortuosum spores is their 1-layered wall surrounded by a peridium. Young spores frequently lack a peridium and then resemble those of Gl. arenarium Blaszk. et al., Gl. etunicatum W.N. Becker & Gerd., Gl. insculptum Blaszk., Gl. mosseae (Nicol. & Gerd.) Gerd. & Trappe, and Gl. versiforme (P. Karsten) S.M. Berch. Although similar in size and colour, all the latter species produce spores with at least two layers of their wall. Additionally, most Gl. tortuosum spores occur in sporocarps. Of the fungi compared here, only Gl. mosseae and Gl. versiforme sometimes form sporocarps. In Gl. mosseae sporocarps, the surface of the peridium is smooth or somewhat roughened when seen in a plane view, and not sinuous as that of Gl. tortuosum. Sporocarps of Gl. versiforme lack a peridium.

REFERENCES

Cabello M. N. 2001. Glomus tortuosum (Glomales), and arbuscular-mycorrhizal fungus (AMF) isolated from hydrocarbon-polluled soils. Nova Hedwigia 73, 513-520.

Koske R. E. 1987. Distribution of VA mycorrhizal fungi along a latitudinal temperature gradient. Mycologia 79, 55-68.

Oehl F., Sieverding E., Ineichen K., Mader P., Boller T., Wiemken A. 2003. Impact of land use intensity on the species diversity of arbuscular mycorrhizal fungi in agroecosystems of Central Europe. Appl. Environ. Microbiol.69, 2816-2824.

Schenck N. C., Smith G. S. 1982. Additional new and unreported species of mycorrhizal fungi (Endogonaceae) from Florida. Mycologia 74, 77-92.

Sridhar K. R., Beena K. R. 2001. Arbuscular mycorrhizal research in coastal sand dunes: a review. Proc. Nat. Acad. Sci. India. 71, 179-205.