Antioxidant enzyme activities as affected by trivalent and hexavalent chromium species in Fontinalis antipyretica Hedw.
The detoxification mechanisms of the aquatic moss, Fontinalis antipyretica Hedw., exposed to Cr was analyzed. In addition, the influence of Cr salts (as Cr nitrate, chloride and potassium bichromate) on these mechanisms has also been studied. The activity of antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1.), catalase (EC 1.11.1.6.), ascorbate peroxidase (APX, EC 1.11.1.11.), guaiacol peroxidase (GPX, EC 1.11.1.7.) and glutathione reductase (GR, EC 1.6.4.2.) increased in plants treated with Cr concentrations ranging from 6.25x10(-5) to 6.25mM when given as Cr(NO3)3. Antioxidant enzymes responded to the other two salts CrCl3 and K2Cr2O7 only with Cr concentrations higher than 6.25x10(-2)mM. Glutathione level and GSSG/GSH ratio also responded to Cr exposure but no dose-effect relationship could be observed. Moreover, two unknown thiol compounds were observed in mosses exposed to the highest Cr concentrations. Effects on chlorophyll contents and chlorophyll a/b ratios were also shown even at low Cr concentrations. Our results indicated that environmentally realistic concentrations of Cr could lead to impairment of the cellular activity towards F. antipyretica and that Cr(III), when present as a nitrate salt, was as harmful as Cr(VI).
Dazy
Marc
M
Université Paul Verlaine-Metz, Laboratoire "Interactions Ecotoxicologie, Biodiversité, Ecosystèmes", CNRS UMR 7146, Campus Bridoux, Rue du Général Delestraint, 57070 Metz, France. dazy@univ-metz.fr
Béraud
Eric
E
Cotelle
Sylvie
S
Meux
Eric
E
Masfaraud
Jean-François
JF
Férard
Jean-François
JF
D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D044002:Bryophyta / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D002374:Catalase / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D002857:Chromium / Q000633:toxicity*; D005980:Glutathione Reductase / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D012989:Soil Pollutants / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D000975:Antioxidants; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D002857:Chromium; D002734:Chlorophyll; D010544:Peroxidases; C121048:guaiacol peroxidase; D060387:Ascorbate Peroxidases; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase