(Nicol. & Gerd.) Gerd. & Trappe
SUBCELLULAR STRUCTURE OF SPORES consists of a spore wall with two layers (swl1 and 2) and one germination wall (gw).
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Layer 1 permanent, smooth, pale yellow (3A2) to pastel yellow (3A4), (2.2-)3.1(-3.4) µm thick, usually adherent to layer 2, sometimes separating from this layer in vigorously crushed spores.
Layer 2 laminate, greenish yellow (1A7-A8), (7.5-)14.6(-24.5) µm thick, staining garnet red (11E8) in Melzer’s reagent.
Germination wall (0.5-)0.8(-1.5) µm thick, sometimes folding or separating from spore wall layer 2, ornamented with evenly distributed warts or knobs projecting inward the spore.
SPOROGENOUS CELL formed terminally on a sparsely septate sporophore; ovoid to clavate; (34.0-)38.0(-47.0) µm wide; concolorous with spore wall layer 2.
Structure of sporogenous cell composed of two layers, continuous with spore wall layers 1 and 2.
Layer 1 pale yellow (3A2) to pastel yellow (3A4), 0.5-0.8 µm thick.
Layer 2 greenish yellow (1A7-A8), (1.6-)3.8(-5.7) µm thick at the spore base.
GERMINATION. A germ tube develops from the germination wall and penetrates the spore wall.
AUXILIARY CELLS. No found.
MYCORRHIZAE. Not established yet. According to Bentivenga and Morton (1995), the mycorrhizae of Gi. gigantea consisted of arbuscules and intraradical hyphae staining darkly in trypan blue.
DISTRIBUTION. In Poland, Gi. gigantea has been recorded under different plants of dune sites of the Baltic Sea coast (Blaszkowski 1990, 1993, 1994; Tadych and Blaszkowski 2000).
This species has commonly occurred in Ammophila breviligulata Fern.-dominated dunes of the Atlantic coast of North America from Quebec to Virginia (Bergen and Koske 1984; Dalpé 1989; Gemma and Koske 1989; Gemma et al. 1989; Koske 1987; Koske and Halvorson 1981). Rose (1980) and Sylvia and Will (1988) found this fungus in dunes of Florida. Gigaspora gigantea has also inhabited dunes of Wisconsin (Koske and Tews 1987) and New South Wales, Australia (Koske 1975).
NOTES. Gigaspora gigantea is the type species of the genus Gigaspora Gerd. & Trappe (Gerdemann and Trappe 1974). The most distinctive characters of Gi. gigantea are the colour and size of its spores. The greenish yellow spore colour is unknown elsewhere in the phylum Glomeromycota. Moreover, this colour is associated with the spore contents rather than with the laminae of the spores as in the other Gigaspora species. Of the five accepted species of the genus Gigaspora (Bentivenga and Morton 1995), Gi. gigantea produces largest spores. Nicolson and Gerdemann (1968) described mature spores of this fungus as being as large as 812 µm diam.
Gigaspora gigantea is the only member of the genus Gigaspora found by one of the authors of this website, J. Blaszkowski, in rhizosphere soils coming from different regions of Europe, Africa, and Asia.
REFERENCES
Bentivenga S. P., Morton J. B. 1995. A monograph of the genus Gigaspora, incorporating developmental patterns of morphological characters. Mycologia 87, 719-731.
Bergen M., Koske R. E. 1984. Vesicular-arbuscular mycorrhizal fungi from sand dunes of Cape Cod, Massachusetts. Trans. Br. Mycol. Soc. 83, 157-158.
Blaszkowski J. 1990. Polish Endogonaceae IV. Gigaspora gigantea, Glomus deserticola, and Glomus globiferum. Acta Mycol 26, 3-16.
Blaszkowski J. 1993. Comparative studies of the occurrence of arbuscular fungi and mycorrhizae (Glomales) in cultivated and uncultivated soils of Poland. Acta Mycol. 28, 93-140.
Blaszkowski J. 1994. Arbuscular fungi and mycorrhizae (Glomales) of the Hel Peninsula, Poland. Mycorrhiza 5, 71-88.
Dalpé Y. 1989. Inventaire et repartition de la flore endomycorhizienne de dunes et de rivages maritimes du Québec, du Nouveau-Brunswick et de la Nouvelle-Ecosse. Naturaliste Can. (Rev. Ecol. Syst.) 116, 219-236.
Gemma J. N., Koske R. E. 1989. Field inoculation of American beachgrass (Ammophila breviligulata) with V-A mycorrhizal fungi. J. Environm. Manag. 29, 173-182.
Gemma J. N., Koske R. E., Carreiro M. 1989. Seasonal dynamics of selected species of VA mycorrhizal fungi in a sand dune. Mycol. Res. 92, 317-321.
Gerdemann J. W., Trappe J. M. 1974. The Endogonaceae in the Pacific Northwest. Myc. Memoir 5, 1-76.
Koske R. E. 1975. Endogone spores in Australian sand dunes. Can J Bot 53, 668-672.
Koske R. E. 1987. Distribution of VA mycorrhizal fungi along a latitudinal temperature gradient. Mycologia 79, 55-68.
Koske R. E., Halvorson W. L. 1981. Ecological studies of vesicular-arbuscular mycorrhizae in a barrier sand dune. Can. J. Bot. 59, 1413-1422.
Koske R. E., Tews L. L. 1987. Vesicular-arbuscular mycorrhizal fungi of Wisconsin sandy soils. Mycologia 79, 901-905.
Nicolson T. H., Gerdemann J. W. 1968. Mycorrhizal Endogone species. Mycologia 60, 313-325.
Rose S. L. 1980. Mycorrhizal associations of some actinomycete nodulated nitrogen-fixing plants. Can. J. Bot. 58, 1449-1454.
Sylvia D. M., Will M. E. 1988. Establishment of vesicular-arbuscular mycorrhizal fungi and other microorganisms on a beach replenishment site in Florida. Appl. Environm. Microbiol. 54, 348-352.
Tadych M., Blaszkowski J. 2000. Arbuscular fungi and mycorrhizae (Glomales) of the Slowinski National Park, Poland. Mycotaxon 74, 463-483.
