title: Toxic effects of Cu(2+) on growth, nutrition, root morphology, and distribution of Cu in roots of Sabi grass.
abstract: Sabi grass (Urochloa mosambicensis (Hack.) Dandy) (a C4 species of Poaceae) is commonly used to revegetate disturbed sites in low-rainfall environments, but comparatively little is known regarding copper (Cu) toxicity in this species. A dilute nutrient solution culture experiment was conducted for 10 d to examine the effects of elevated Cu(2+) activities ({Cu(2+)}) on the growth of Sabi grass. Growth was inhibited by high Cu in solution, with a 50% reduction in the relative fresh mass occurring at 1.0 microM {Cu(2+)} for the roots and 1.2 microM {Cu(2+)} for the shoots. In solutions containing 1.2-1.9 microM {Cu(2+)}, many of the roots ruptured due to the tearing and separation of the rhizodermis and outer cortex from the underlying tissues. Transmission electron microscopy revealed that Cu-rich deposits were found to accumulate predominantly within vacuoles. Due to limited translocation of Cu from the roots to the shoots, phytotoxicity is likely to be more of a problem in remediation of Cu-toxic sites than is Cu toxicity of fauna consuming the above-ground biomass.
authors.affiliation: School of Land, Crop and Food Sciences, The University of Queensland, St. Lucia, Queensland 4072, Australia. p.kopittke@uq.edu.au
authors.forename: P M
authors.initials: PM
authors.lastname: Kopittke
authors.forename: C J
authors.initials: CJ
authors.lastname: Asher
authors.forename: F P C
authors.initials: FP
authors.lastname: Blamey
authors.forename: N W
authors.initials: NW
authors.lastname: Menzies
mesh_terms: D003300:Copper / Q000493:pharmacokinetics / Q000633:toxicity*; D004785:Environmental Pollutants / Q000493:pharmacokinetics / Q000633:toxicity*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008954:Models, Biological; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D018520:Plant Shoots / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D006109:Poaceae / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D013054:Spectrophotometry, Atomic
chemical_list: D004785:Environmental Pollutants; D003300:Copper; C029892:cupric chloride