Assessment of copper tolerance of two populations of Oenothera picensis Phil. subsp. picensis (Onagraceae)

Abstract

Oenothera picensis Phil. subsp. picensis can grow in soils that have been contaminated with copper from the metal smelting
industry in central Chile, presenting characteristics that make it a candidate for phytoremediation processes. In order to
know the real tolerance and capacity for copper extraction and to identify whether this characteristic is present solely
in the exposed population, a hydroponic test was carried out using two populations of O. picensis, originated from Los
Maitenes and Maitencillo, areas with high and normal Cu concentrations in the soil, respectively. The plants were exposed
to copper concentration in solution between 0 and 0.16 mM, for one month. The plants presented symptoms of toxicity
at 0.04 mM of Cu in the solution, without significant differences in the tolerance of both populations. The shoot copper
concentrations observed in O. picensis reached the maximum of 1660±857 mg kg-1, in the treatment of 0.16 mM of Cu in
the solution. However, in this treatment, the plant presented severe toxicity symptoms. Thus, it is not possible to classify it
as a hyperaccumulating species.