Role of glutathione in tolerance to arsenite in Salvinia molesta, an aquatic fern

In many plant species, tolerance to toxic metals is highly dependent on glutathione, an essential metabolite for cellular detoxifi cation. We evaluated the responses of glutathione metabolism to arsenite (As III ) in Salvinia molesta , an aquatic fern that has unexplored phytoremediation potential. Plants were exposed to diff erent As III concentrations in nutrient solution for 24 h. As III caused cell membrane damage to submerged leaves, indicating oxidative stress. Th ere was an increase in the glutathione content and ϒ-glutamylcysteine synthetase enzyme activity in the submerged and fl oating leaves. Th e glutathione peroxidase and glutathione sulfotransferase enzymes also showed increased activity in both plant parts, whereas glutathione reductase only showed increased activity in the submerged leaves. Th ese fi ndings suggest an important role for glutathione in the protection of S. molesta against the toxic eff ects of As III , with more eff ective tolerance responses in the fl oating leaves.