title: Relative tolerance of a range of Australian native plant species and lettuce to copper, zinc, cadmium, and lead.
abstract: The tolerance of wild flora to heavy-metal exposure has received very little research. In this study, the tolerance of four native tree species, four native grass species, and lettuce to copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) was investigated in a root-elongation study using Petri dishes. The results of these studies show a diverse range of responses to Cu, Zn, Cd, and Pb amongst the tested plant species. Toxicity among metals decreased in the following order: Cd ~ Cu > Pb > Zn. Metal concentrations resulting in a 50% reduction in growth (EC(50)) varied considerably, ranging from (microM) 30 (Dichanthium sericeum) to >2000 (Acacia spp.) for Cu; from 260 (Lactuca sativa) to 2000 (Acacia spp.) for Zn; from 27 (L. sativa) to 940 (Acacia holosericea) for Cd; and from 180 (L. sativa) to >1000 (Acacia spp.) for Pb. Sensitive native plant species identified included D. sericeum, Casuarina cunninghamiana, and Austrodanthonia caespitosa. However, L. sativa (lettuce) was also among the most sensitive to all four metals. Acacia species showed a high tolerance to metal exposure, suggesting that the Acacia genus shows potential for use in contaminated-site revegetation.
authors.affiliation: Centre for Environmental Risk Assessment and Remediation, University of South Australia, Adelaide, Australia.
authors.forename: Dane T
authors.initials: DT
authors.lastname: Lamb
authors.forename: Hui
authors.initials: H
authors.lastname: Ming
authors.forename: Mallavarapu
authors.initials: M
authors.lastname: Megharaj
authors.forename: Ravi
authors.initials: R
authors.lastname: Naidu
mesh_terms: D001315:Australia; D002104:Cadmium / Q000633:toxicity; D003300:Copper / Q000633:toxicity; D018525:Germination / Q000187:drug effects; D007854:Lead / Q000633:toxicity; D018545:Lactuca / Q000187:drug effects / Q000254:growth & development; D019216:Metals, Heavy / Q000633:toxicity*; D063245:Plant Development; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D010944:Plants / Q000187:drug effects*; D006109:Poaceae / Q000187:drug effects / Q000254:growth & development; D012989:Soil Pollutants / Q000633:toxicity*; D018675:Toxicity Tests; D014197:Trees / Q000187:drug effects / Q000254:growth & development; D015032:Zinc / Q000633:toxicity
chemical_list: D019216:Metals, Heavy; D012989:Soil Pollutants; D002104:Cadmium; D007854:Lead; D003300:Copper; D015032:Zinc