Increase in ascorbate-glutathione metabolism as local and precocious systemic responses induced by cadmium in durum wheat plants. Plant Cell Physiol

grown in the presence of cadmium (0–40kM) and analysed after 3 and 7 d for their growth, oxidative stress markers, phytochelatins, and enzymes and metabolites of the ascorbate (ASC)–glutathione (GSH) cycle. Cd exposure produced a dose-dependent inhibition of growth in both roots and leaves. Lipid peroxidation, protein oxidation and the decrease in the ascorbate redox state indicate the presence of oxidative stress in the roots, where H2O2 overproduction and phytochelatin synthesis also occurred. The activity of the ASC–GSH cycle enzymes significantly increased in roots. Consistently, a dose-dependent accumulation of Cd was evident in these organs. On the other hand, no oxidative stress symptoms or phytochelatin synthesis occurred in the leaves; where, at least during the time of our analysis, the levels of Cd remained irrelevant. In spite of this, enzymes of the ASC–GSH cycl