Premium
Effects of pH on uranium uptake and oxidative stress responses induced in Arabidopsis thaliana
Author(s) -
Saenen Eline,
Horemans Nele,
Vanhoudt Nathalie,
Vandenhove Hildegarde,
Biermans Geert,
Van Hees May,
Wannijn Jean,
Vangronsveld Jaco,
Cuypers Ann
Publication year - 2013
Publication title -
environmental toxicology and chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 171
eISSN - 1552-8618
pISSN - 0730-7268
DOI - 10.1002/etc.2290
Subject(s) - glutathione , arabidopsis thaliana , oxidative stress , chromosomal translocation , catalase , glutathione reductase , superoxide dismutase , chemistry , phytochelatin , genetic algorithm , environmental chemistry , antioxidant , toxicity , uranium , biochemistry , botany , biology , glutathione peroxidase , enzyme , ecology , mutant , gene , organic chemistry , materials science , metallurgy
Uranium (U) causes oxidative stress in Arabidopsis thaliana plants grown at pH 5.5. However, U speciation and its toxicity strongly depend on environmental parameters, for example pH. It is unknown how different U species determine U uptake and translocation within plants and how they might affect the oxidative defense mechanisms of these plants. The present study analyzed U uptake and oxidative stress‐related responses in A. thaliana (Columbia ecotype) under contrasted U chemical speciation conditions. The 18‐d‐old seedlings were exposed for 3 d to 25 µM U in a nutrient solution of which the pH was adjusted to 4.5, 5.5, 6.5, or 7.5. Results indicate that there is a different rate of U uptake and translocation at the different pHs, with high uptake and low translocation at low pH and lower uptake but higher translocation at high pH. After U exposure, an increased glutathione reductase activity and total glutathione concentration were observed in U‐exposed roots, pointing toward an important role for glutathione in the root defense system against U either by chelation or by antioxidative defense mechanisms. In leaves, antioxidative defense mechanisms were activated on U exposure, indicated by increased superoxide dismutase and catalase activity. As it seems that U toxicity is influenced by pH, it is important to consider site‐specific characteristics when making U risk assessments. Environ Toxicol Chem 2013;32:2125–2133. © 2013 SETAC