Deficiency and toxicity of nanomolar copper in low irradiance-A physiological and metalloproteomic study in the aquatic plant Ceratophyllum demersum.
Essential 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 7.5-35nM Cu, while PSII activity (Fv/Fm) was maximal around 7.5nM Cu. Damage to the light harvesting complex of photosystem II (LHCII) was the first target of Cu toxicity (>50nM 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 (ΦPSII). The pigment decrease added to the damage in the photosynthetic light reactions. These mechanisms ultimately resulted in decrease of starch and oxygen production.
University of Konstanz, Department of Biology, D-78457 Konstanz, Germany.
George
G
Thomas
University of Konstanz, Department of Biology, D-78457 Konstanz, Germany; Institute of Plant Molecular Biology, Department Plant Biophysics and Biochemistry, Biology Centre of the ASCR, Branišovská 31/1160, CZ-37005 České Budějovice, Czech Republic.
Elisa
E
Andresen
UFZ - Helmholtz Centre for Environmental Research, Department of Analytical Chemistry, Permoserstr. 15, D-04318 Leipzig, Germany.
Jürgen
J
Mattusch
Institute of Hydrobiology, Department of Hydrochemistry and Ecosystem Modelling, Biology Centre of the ASCR, Na Sádkách 7, 37005 České Budějovice, Czech Republic; SoWa National Research Infrastructure, Biology Centre of the ASCR, Na Sádkách 7, 37005 České Budějovice, Czech Republic.
Tomáš
T
Hubáček
University of Konstanz, Department of Biology, D-78457 Konstanz, Germany; Institute of Plant Molecular Biology, Department Plant Biophysics and Biochemistry, Biology Centre of the ASCR, Branišovská 31/1160, CZ-37005 České Budějovice, Czech Republic; University of South Bohemia, Faculty of Biological Science, Branišovská 31/1160, CZ-37005 České Budějovice, Czech Republic. Electronic address: Hendrik.Kuepper@umbr.cas.cz.
Hendrik
H
Küpper
D059001:Aquatic Organisms / Q000187:drug effects / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D003300:Copper / Q000737:chemistry / Q000172:deficiency / Q000633:toxicity*; D008027:Light; D019684:Magnoliopsida / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D010788:Photosynthesis / Q000187:drug effects / Q000502:physiology; D020543:Proteome / Q000187:drug effects* / Q000378:metabolism; D040901:Proteomics; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000633:toxicity*
D015415:Biomarkers; D020543:Proteome; D014874:Water Pollutants, Chemical; D003300:Copper
Biophysics of photosynthesis; Ceratophyllum demersum; Chlorophyll fluorescence kinetics; Copper deficiency; Metalloproteomics; Physiological stress