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Applied and Environmental Microbiology, June 2000, p. 2526-2530, Vol. 66, No. 6
Department of Plant Biology, University of
Minnesota, St. Paul, Minnesota 551081;
Environmental Chemistry Laboratory, USDA Agricultural Research
Service, Beltsville Agricultural Research Center West, Beltsville,
Maryland 207052; and 125 Rivington St.,
New York, New York 100023
Received 17 November 1999/Accepted 6 April 2000
Phytoextraction involves use of plants to remove toxic metals from
soil. We examined the effects of phytoextraction practices with three
plant species (Silene vulgaris, Thlaspi
caerulescens, and Zea mays) and a factorial variation
of soil amendments (either an ammonium or nitrate source of nitrogen
and the presence or absence of an elemental sulfur supplement) on
arbuscular mycorrhizal (AM) fungi (Glomales, Zygomycetes) at a
moderately metal-contaminated landfill located in St. Paul, Minn.
Specifically, we tested whether the applied treatments affected the
density of glomalean spores and AM root colonization in maize.
Glomalean fungi from the landfill were grouped into two morphotypes
characterized by either light-colored spores (LCS) or dark-colored
spores (DCS). Dominant species of the LCS morphotype were Glomus
mosseae and an unidentified Glomus sp., whereas the
DCS morphotype was dominated by Glomus constrictum. The
density of spores of the LCS morphotype from the phytoremediated area
was lower than the density of these spores in the untreated landfill
soil. Within the experimental area, spore density of the LCS morphotype
in the rhizosphere of mycorrhizal maize was significantly higher than
in rhizospheres of nonmycorrhizal S. vulgaris or T. caerulescens. Sulfur supplement increased vesicular root
colonization in maize and exerted a negative effect on spore density in
maize rhizosphere. We conclude that phytoextraction practices, e.g.,
the choice of plant species and soil amendments, may have a great
impact on the quantity and species composition of glomalean propagules
as well as on mycorrhiza functioning during long-term metal-remediation treatments.
0099-2240/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Effects of Metal Phytoextraction Practices on the
Indigenous Community of Arbuscular Mycorrhizal Fungi at a
Metal-Contaminated Landfill

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Corresponding author. Mailing address: Department of
Plant Biology, University of Minnesota, 220 Biological Sciences Center, 1445 Gortner Ave., St. Paul, MN 55108-1095. Phone: (612) 625-3199. Fax:
(612) 625-1738. E-mail: charv001{at}maroon.tc.umn.edu.
Present address: Department of Plant and Microbial Biology,
University of California, Berkeley, CA 94720.
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