Glomus aggregatum

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

SPORES borne singly in the soil, in aggregates, in roots, forming inside of spores by internal proliferation or inside of extraradical hyphae as intercalary subglobose swellings.

Aggregates 160-1600 x 250-1900 µm, without a peridium, with two to over one hundred spores loosely distributed.

Spores pastel yellow (2A4) to yellowish brown (5D8); mostly globose to subglobose; (40-)86(-150) µm diam, rarely pyriform to irregular; 70-100 x 100-160 µm; usually with a single subtending hypha, rarely with two.

SUBCELLULAR STRUCTURE OF SPORES composed of a spore wall including three layers (swl1-3).

In PVLG
In PVLG+Melzer's
In PVLG+Melzer's

Layer 1 mucilaginous, hyaline, (0.5-)1.2(-2.4) µm thick, staining pink (12A4) to purplish red (14A8) in Melzer’s reagent, usually highly deteriorated or absent in mature spores.

Layer 2 semiflexible, hyaline, (0.5-)1.2(-2.4) µm thick, degrading with age; in mature spores, this layer frequently becomes granular and occurs in patches.

Layer 3 laminate, smooth, pastel yellow (2A4) to yellowish brown (5D8), (2.0-)3.2(-4.4) µm thick.

The spore wall structure of inside spores is as that of their parent spores.

SUBTENDING HYPHA pastel yellow (2A4) to yellowish brown (5D8); straight or curved; cylindrical to funnel-shaped, rarely constricted or swollen at the spore base; (6.4-)14.3(-21.6) µm wide at the spore base when funnel-shaped, (5.0-)11.2(-18.5) µm wide at the constriction near the spore base and (3.8-)15.1(-27.5) µm wide at its inflated part.
In PVLG
In PVLG+Melzer's
Wall of subtending hypha pastel yellow (2A4) to yellowish brown (5D8); (1.2-)3.3(-5.6) µm thick at the spore base; composed of three layers, continuous with layers 1-3 of the spore wall.

Pore (1.5-)5.5(-12.5) µm wide, usually open, sometimes closed by a curved septum continuous with the innermost lamina of the laminate spore wall layer 3 or by a thin septum formed some distance down the spore base.

Inner spores form blastically from the tip of a hypha developing from the subtending hypha of the parent spore.
In PVLG

GERMINATION. A germ tube emerges from the lumen of the subtending hypha.

 

 

In roots of P. lanceolata

MYCORRHIZAE. In roots of Plantago lanceolata L., mycorrhizae of Gl. aggregatum consisted of arbuscules, intra- and abundant extraradical hyphae staining moderately to intensively in 0.1% trypan blue. No vesicles were found.

 

 

DISTRIBUTION. In Poland, Gl. aggregatum has been found among roots of many plants colonizing the Baltic Sea coast (Blaszkowski 1991, 1993a, 1994, 1995; Blaszkowski et al. 2002a; Tadych and Blaszkowski 2000a) and sandy soils of the banks of the Odra river (Blaszkowski 1991). It has been commonly associated with cultivated plants of Poland (Blaszkowski 1993b). This fungus has been the third species in frequency of occurrence in soils of the Bledowska Desert (50o22’N, 19o34’E; Blaszkowski et al. 2002b). Additionally, Gl. aggregatum spores have been encountered in soils of the Tuchola Forests (53o46’N, 17o42’E-53o40’N, 17o54’E; Tadych and Blaszkowski 2000b).

Glomus aggregatum has regularly occurred in dunes of the eastern coast of North America (Dalpé 1989; Friese and Koske 1991; Gemma and Koske 1989; Koske 1985, 1987; Sylvia 1986; Sylvia and Will 1988), Wisconsin (Koske and Tews 1987), San Miguel Island (Halvorson and Koske 1987; Koske and Halvorson 1989), and Hawaii (Koske 1988).

NOTES. Glomus aggregatum is most similar to Gl. intraradices N.C. Schenck & G.S. Sm. and Gl. hoi S.M. Berch & Trappe. All the species produce yellow-coloured spores of a similar size range and the spores may occur both singly and in aggregates in the soil (Berch and Trappe 1985; Blaszkowski 1991; Koske 1985; Schenck and Smith 1982). However, only Gl. aggregatum forms spores inside its parent spores by internal proliferation.

REFERENCES

Berch S. M., Trappe J. M. 1985. A new species of Endogonaceae, Glomus hoi. Mycologia 77, 654-657.

Blaszkowski J. 1991. Polish Endogonaceae. IX. Glomus aggregatum with spores forming an evanescent outermost wall. Crypt. Bot. 2/3, 130-135.

Blaszkowski J. 1993a. The occurrence of arbuscular fungi and mycorrhizae (Glomales) in plant communities of maritime dunes and shores of Poland. Bull. Pol. Ac. Sci. Biol. Sci. 41, 377-392.

Blaszkowski J. 1993b. 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.

Blaszkowski J. 1995. Glomus corymbiforme, a new species in Glomales from Poland. Mycologia 87, 732-737.

Blaszkowski J., Adamska I., Czerniawska B. 2002a. Arbuscular mycorrhizal fungi (Glomeromycota) of the Vistula Bar. Acta Mycol. 37, 39-62.

Blaszkowski J., Tadych M., Madej T. 2002b. Arbuscular mycorrhizal fungi (Glomales, Zygomycota) of the Bledowska Desert, Poland. Acta Soc. Bot. Pol. 71, 71-85.

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.

Friese C. F., Koske R. E. 1991. The spatial dispersion of spores of vesicular-arbuscular mycorrhizal fungi in a sand dune: microscale patterns associated with the root architecture of American beachgrass. Mycol. Res. 95, 952-957.

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.

Halvorson W. L., Koske R. E. 1987. Mycorrhizae associated with an invasion of Erechtites glomerata (Asteraceae) on San Miguel Island, California. Madrono 34, 260-268.

Koske R. E. 1985. Glomus aggregatum emended: A distinct taxon in the Glomus fasciculatum complex. Mycologia 77, 619-630.

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

Koske R. E. 1988. Vesicular-arbuscular mycorrhizae of some Hawaiian dune plants. Pacific Sci. 42, 217-229.

Koske R. E., Halvorson W. L. 1989. Mycorrhizal associations of selected plant species from San Miguel Island, Channel Islands National Park, California. Pacific Sci. 43, 32-40.

Koske R. E., Tews L. L. 1987. Vesicular-arbuscular mycorrhizal fungi of Wisconsin sandy soils. Mycologia 79, 901-905.

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

Sylvia D. M. 1986. Spatial and temporal distribution of vesicular-arbuscular mycorrhizal fungi associated with Uniola paniculata in Florida foredunes. Mycologia 78, 728-734.

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. 2000a. Arbuscular fungi and mycorrhizae (Glomales) of the Slowinski National Park, Poland. Mycotaxon 74, 463-483.

Tadych M., Blaszkowski J. 2000b. Arbuscular mycorrhizal fungi of the Brda river valley in the Tuchola Forests. Acta Mycol. 35, 3-23.