Characterization of Phytoavailable Copper in Compost-Peat Substrates and Determination of a Toxicity Level
Year: 2000
Type: article
Abstract: Heavy metal-sensitive `Express Orchid' petunias ( Petunia × hybrida Hort Vilm.-Andr. `Express Orchid') were grown in substrates of 2 green yard waste compost: 3 peat (v/v) with target Cu contents of 100 and 200 mg·kg -1 at varying pH. Iron supply was also varied. Copper contents of the substrate were determined by H 2 O, NH 4 NO 3 , NH 4 OAc, CaCl 2 , CaCl 2 -DTPA, and aqua regia extraction. Plant Cu concentration increased with increasing Cu supply and decreasing pH, indicating that Cu phytoavailability depended on substrate pH. Extraction of fresh substrates with CaCl 2 -DTPA provided a good prediction of plant Cu concentration and reflected well the influence of pH on Cu phytoavailability. The percentage of CaCl 2 -DTPA extractable Cu increased with decreasing pH. Extractions of Cu with NH 4 NO 3 , H 2 O, NH 4 OAc, and CaCl 2 resulted in very low extractable amounts and hence were not suitable. Plants showed Cu toxicity induced iron-like deficiency chlorosis, which was alleviated by additional Fe supply. This Fe supply did not seem to affect total Fe concentration of petunias, but reduced Cu concentration of the shoots. Since yield reduction was not observed, the occurrence of chlorosis during the culture period was chosen as the toxicity parameter, resulting in a Cu threshold toxicity level of 12.3 mg . kg -1 plant dry weight. From this, a threshold toxicity level for CaCl 2 -DTPA extractable Cu in compost-peat substrates of 3 mg . L -1 substrate was determined. Chemical name used: diethylenetriamine-pentaacetic acid (DTPA).
Authors: Annette S. Bucher, Manfred K. Schenk
Institution: Leibniz University Hannover
Language: English
Topic: Heavy metals in environment
Subfield: Pollution
Field: Environmental Science
Domain: Physical Sciences
SDG: Zero hunger
Open Access status: gold
Estimated APC paid: $3,500
OpenAlex ID: W2157522155