Authors: Shuang Zhang Chong Bin Qiu You Zhou Zhen Peng Jin Hong Yang
Publish Date: 2010/12/09
Volume: 20, Issue: 2, Pages: 337-347
Abstract
The herbicide fluroxypyr is widely used for controlling weeds and insects but intensive use of fluroxypyr has resulted in its widespread contamination in soils and aquatic ecosystems To evaluate the ecotoxicity of fluroxypyr to green algae bioaccumulation and degradation of fluroxypyr in Chlamydomonas reinhardtii a model unicellular alga along with its biological adaptation to fluroxypyr toxicity were investigated The microalgae were treated with fluroxypyr at 005–100 mg l−1 for 2 days or 050 mg l−1 for 1–5 days The growth of C reinhardtii was stimulated at low levels of fluroxypyr 005–05 mg l−1 but inhibited at high concentrations 075–100 mg l−1 Fluroxypyr was significantly accumulated by C reinhardtii Interestingly the accumulated fluroxypyr could be rapidly degraded in the cells On day 5 more than 57 of cellular fluroxypyr was degraded Our results indicated that accumulation and degradation of fluroxypyr occurred simultaneously Treatment with 005–100 mg l−1 fluroxypyr for 30 min induced significant production of reactive oxygen species and as a consequence resulted in accumulation of peroxides and DNA degradation Additionally activities of several major antioxidant enzymes were activated in C reinhardtii exposed to high levels of fluroxypyr Overall the present studies represent the initial comprehensive analyses of the green alga C reinhardtii in adaptation to the fluroxypyrcontaminated aquatic ecosystems
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