Submitted to: Abstract of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2001
Publication Date: November 22, 2001
Technical Abstract:
Metal hyperaccumulator plants like Alyssum murale are used for phytoremediation of Ni contaminated soils. Soil microorganisms are known to play an important role in nutrient acquisition for plants, however, little is known about the rhizosphere microorganisms of hyperaccumulators. Total number of viable bacteria (12 x 109 g-1), numbers of Ni-resistant bacteria at 8mM NiCl2 (1.6 x 109 g-1) and % acid producing bacteria (78 %) were higher in rhizosphere soil compared to bulk soil (2 x 105 g-1), 6 x 104 g-1 and 42 %), respectively. Nickel sensitive and non-acid bacteria were higher in bulk soil than in rhizosphere soil. The number of Gram-positive, Gram- negative bacteria, siderophore producing, and phosphate solubilizing bacteria were not affected by the presence of the plant. The pH of bulk soil was slightly higher than the rhizosphere soil. Soil acidification of the rhizosphere could affect metal uptake by increasing metal availability around the roots, which would also explain the observed selection for metal resistant bacteria.
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