Toxic effects of Cu super(2) super(+) on growth, nutrition, root morphology, and distribution of Cu in roots of Sabi grass

• Published in: The Science of the total environment 2009-08, Vol.407 (16), p.4616-4621
• Main Authors: Kopittke, P M, Asher, C J, Blamey, FPC, Menzies, N W
• Format: Article
• Language: English
• Subjects: Poaceae; Urochloa
• ISSN: 0048-9697
• DOI: 10.1016/j.scitotenv.2009.04.041

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 super(2) super(+) activities ({Cu super(2) super(+)}) 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 kM {Cu super(2) super(+)} for the roots and 1.2 kM {Cu super(2) super(+)} for the shoots. In solutions containing 1.2-1.9 kM {Cu super(2) super(+)}, 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. spectroscopy/-mass spectrometry