|Mckenna, Mary - BIOLOGY DEPT, HOWARD|
|Brewer, Eric - UMD COLLEGE PARK|
Submitted to: Abstracts for New Phytologist Symposium
Publication Type: Abstract Only
Publication Acceptance Date: September 30, 2002
Publication Date: September 30, 2002
Technical Abstract: Several species of nickel hyperaccumulators in the genus Alyssum are found on serpentine (ultramafic) soils throughout southern and eastern Europe and Asia, and some are endemic to serpentine substrates. This study examines the extent to which physiological factors restrict nickel hyperaccumulators to soil with high nickel concentrations. Two species of Alyssum were compared: A corsicum , a serpentine endemic with restricted distribution in Turkey and Corsica (Reeves, 1992) and (2) A. murale, a widespread species on serpentine soils in southern Europe and Asia that also grows in non-serpentine areas in the Balkans (Brooks, 1998). Vegetative and reproductive characteristics of these two Alyssum species were compared in soil treatments with experimentally controlled nickel levels created by mixing nickel salts (1:1 nickel sulfate and nickel acetate) with fertilized sandy loam soil (pH 8.5) to produce a high nickel treatment (500 mg Ni/kg added), medium nickel treatment (50 mg Ni/kg added ) and low nickel treatment (no nickel added). Both species germinated well without nickel and vegetative growth was not significantly different in high and low nickel soils. Nickel concentrations in vegetative and reproductive tissues measured by ICP increase with soil nickel concentrations. Results of more than 2000 hand crosses indicate that both species are self-incompatible, the proportion of flowers that set seed is low, and seed production in high nickel soil is significantly greater than in medium nickel soil.