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Uranium and cadmium provoke different oxidative stress responses in L emna minor L.
Author(s) -
Horemans N.,
Van Hees M.,
Van Hoeck A.,
Saenen E.,
De Meutter T.,
Nauts R.,
Blust R.,
Vandenhove H.
Publication year - 2015
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/plb.12222
Subject(s) - catalase , oxidative stress , superoxide dismutase , cadmium , glutathione reductase , peroxidase , antioxidant , glutathione peroxidase , biology , biochemistry , oxidative phosphorylation , enzyme , chemistry , organic chemistry
Common duckweed ( L emna minor L.) is ideally suited to test the impact of metals on freshwater vascular plants. Literature on cadmium (Cd) and uranium (U) oxidative responses in L . minor are sparse or, for U, non‐existent. It was hypothesised that both metals impose concentration‐dependent oxidative stress and growth retardation on L . minor . Using a standardised 7‐day growth inhibition test, the adverse impact of these metals on L . minor growth was confirmed, with EC 50 values for Cd and U of 24.1 ± 2.8 and 29.5 ± 1.9 μ m , respectively, and EC 10 values of 1.5 ± 0.2 and 6.5 ± 0.9 μ m , respectively. The metal‐induced oxidative stress response was compared through assessing the activity of different antioxidative enzymes [catalase, glutathione reductase, superoxide dismutase ( SOD ), ascorbate peroxidase ( APOD ), guaiacol peroxidase ( GPOD ) and syringaldizyne peroxidase ( SPOD )]. Significant changes in almost all antioxidative enzymes indicated their importance in counteracting the U‐ and Cd‐imposed oxidative burden. However, some striking differences were also observed. For activity of APOD s and SOD s, a biphasic but opposite response at low Cd compared to U concentrations was found. In addition, Cd (0.5–20 μ m ) strongly enhanced plant GPOD activity, whereas U inhibited it. Finally, in contrast to Cd, U up to 10 μ m increased the level of chlorophyll a and b and carotenoids. In conclusion, although U and Cd induce similar growth arrest in L . minor , the U‐induced oxidative stress responses, studied here for the first time, differ greatly from those of Cd.