title: Effect of heavy metals on seed germination and seedling growth of common ragweed and roadside ground cover legumes.
abstract: In southern Québec, supplement roadside ground covers (i.e. Trifolium spp.) struggle to establish near edges of major roads and thus fail to assist turf recruitment. It creates empty niches vulnerable to weed establishment such as common ragweed (Ambrosia artemisiifolia). We hypothesized that heavy metal stresses may drive such species shifts along roadside edges. A growth chamber experiment was conducted to assess effects of metals (Zn, Pb, Ni, Cu, and Cd) on germination and seedling behaviors of roadside weed (A. artemisiifolia) and ground cover legumes (Coronilla varia, Lotus corniculatus, and Trifolium arvense). All metals inhibited T. arvense germination, but the effect was least on A. artemisiifolia. Low levels of Pb and Ni promoted germination initiation of A. artemisiifolia. Germination of L. corniculatus was not affected by Zn, Pb, and Ni, but inhibited by Cu and Cd. Germination of C. varia was decreased by Ni, Cu, and Cd and delayed by Zn and Pb. Metal additions hindered seedling growth of all test species, and the inhibitory effect on the belowground growth was greater than on the aboveground growth. Seedling mortality was lowest in A. artemisiifolia but highest in T. arvense when exposed to the metal treatments. L. corniculatus and C. varia seedlings survived when subjected to high levels of Zn, Pb, and Cd. In conclusion, the successful establishment of A. artemisiifolia along roadside edges can be associated with its greater tolerance of heavy metals. The findings also revealed that L. corniculatus is a potential candidate for supplement ground cover in metal-contaminated roadside edges in southern Québec, especially sites contaminated with Zn and Pb.
authors.affiliation: Department of Plant Science, McGill University (Macdonald Campus), 21111 Lakeshore Roads, Ste. Anne de Bellevue, Québec H9X 3V9, Canada.
authors.forename: Jichul
authors.initials: J
authors.lastname: Bae
authors.affiliation: Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, 430 Gouin Boulevard, Saint-Jean-sur-Richelieu, Québec J3B 3E6, Canada.
authors.forename: Diane L
authors.initials: DL
authors.lastname: Benoit
authors.affiliation: Department of Plant Science, McGill University (Macdonald Campus), 21111 Lakeshore Roads, Ste. Anne de Bellevue, Québec H9X 3V9, Canada. Electronic address: alan.watson@mcgill.ca.
authors.forename: Alan K
authors.initials: AK
authors.lastname: Watson
mesh_terms: D031164:Ambrosia / Q000737:chemistry*; D007887:Fabaceae / Q000187:drug effects* / Q000254:growth & development*; D018525:Germination / Q000187:drug effects*; D019216:Metals, Heavy / Q000032:analysis / Q000633:toxicity*; D011792:Quebec; D036226:Seedlings / Q000187:drug effects* / Q000254:growth & development*; D012639:Seeds / Q000737:chemistry; D012989:Soil Pollutants / Q000633:toxicity
chemical_list: D019216:Metals, Heavy; D012989:Soil Pollutants
keywords: Ambrosia artemisiifolia; Germination; Heavy metal; Seedling growth; Seedling mortality; Supplement ground cover