Copper- and arsenate-induced oxidative stress in Holcus lanatus L. clones with differential sensitivity

The biochemical responses of Holcus lanatus L, to copper and arsenate expos ure were investigated in arsenate-tolerant and -non-tolerant plants from un contaminated and arsenic/copper-contaminated sites. Increases in lipid pero xidation, superoxide dismutase (SOD) activity and phytochelatin (PC) produc tion were correlated with increasing copper and arsenate exposure. In addit ion, significant differences in biochemical responses were observed between arsenate-tolerant and -non-tolerant plants, Copper and arsenate exposure l ed to the production of reactive oxygen species, resulting in significant l ipid peroxidation in non-tolerant plants, However, SOD activity was suppres sed upon metal exposure, possibly due to interference with metallo-enzymes, It was concluded that in non-tolerant plants, rapid arsenate influx result ed in PC production, glutathione depletion and lipid peroxidation, This pro cess would also occur in tolerant plants, but by decreasing the rate of inf lux, they were able to maintain their constitutive functions, detoxify the metals though PC production and quench reactive oxygen species by SOD activ ity.