Deficiency and toxicity of nanomolar copper in low irradiance—A physiological and metalloproteomic study in the aquatic plant Ceratophyllum demersum

Abstract

a b s t r a c tEssential trace elements (Cu 2+ , Zn 2+ , etc) lead to toxic effects above a certain threshold, which is a major environmental problem in many areas of the world. Here, environmentally relevant sub-micromolar concentrations of Cu 2+ and simulations of natural light and temperature cycles were applied to the aquatic macrophyte Ceratophyllum demersum a s a model for plant shoots. In this low irradiance study resembling non-summer conditions, growth was optimal in the range 7.5-35 nM Cu, while PSII activity (F v /F m ) was maximal around 7.5 nM Cu. Damage to the light harvesting complex of photosystem II (LHCII) was the first target of Cu toxicity (>50 nM Cu) where Cu replaced Mg in the LHCII-trimers. This was associated with a subsequent decrease of Chl a as well as heat dissipation (NPQ). The growth rate was decreased from the first week of Cu deficiency. Plastocyanin malfunction due to the lack of Cu that is needed for its active centre was the likely cause of diminished electron flow through PSII ( PSII ). The pigment decrease added to the damage in the photosynthetic light reactions. These mechanisms ultimately resulted in decrease of starch and oxygen production.

Phytostabilization—Management Strategy for Stabilizing Trace Elements in Contaminated Soils

“…Cu ions are among the microelements characterized by the lowest mobility in soil. Released during the aeration process, Cu 2+ ions bind with soil organic substance, which strongly influences the assimilability of Cu by plants [ 67 ]. Increased bioavailability of Cu to plants is caused by increased soil acidity.…”

Myriophyllum alterniflorum biochemical changes during in vitro Cu/Cd metal stress: Focusing on cell detoxifying enzymes

“…Afterwards, a large stress due to O2• − , •OH and H2O2, probably in both chloroplasts and mitochondria, could be clearly observed during the last week for high Cu concentrations. Indeed, the strong impact of this pollutant on these organelles were several times reported, for example, in Ceratophyllum demersum (Cu toxicity damages, before anything else, the reaction centre of the photosystem II; Thomas et al, 2013Thomas et al, , 2016 or in Pistia stratiotes (exposure to elevated concentration of Cu produced ultrastructural changes -shrinkage and distortion -of chloroplast and mitochondria; Upadhyay and Panda, 2009). This increase also occurred during Cd treatments, albeit to a lesser extent.…”

Analysis of trace metal distribution in plants with lab-based microscopic X-ray fluorescence imaging

“…In order to avoid contaminations, the ICP-MS is located in a cleanroom with air filtration. All measurements follow a "metal free" protocol, proved in earlier works involving metal deficiency [29], which forbids metal tools and is using Polytetrafluoroethylene (PTFE) tools and vials made from PFA (Perfluoroalkoxy alkanes; Savillex, Eden Prairie, MN, USA) because of their low metal contamination.…”