Cadmium uptake, localization and detoxification in Populus × canescens

Phytochelatins (PCs) are heavy metal binding peptides that play an important role in sequestration and detoxification of heavy metals in plants. After 12- week cultivation, the plants were treated with five CdSO 4 ·7 H 2 O concentrations of 0 (control), 10, 30, 50 and 70 µM for 28 days. In this study, the effect of cadmium (Cd) on growth and contents of glutathione (GSH) and phytochelatins (PCs) were investigated in roots, bark, wood and leaves of Populus × canescens. The accumulation of Cd increased with external Cd concentrations and was considerably higher in roots than in bark, wood and leaves. Dry mass production decreased under Cd treatment especially in leaves. In roots, bark, wood and leaves, exposure to Cd caused an appreciable decline in GSH contents and an increase in PCs synthesis proportional to Cd concentrations in the growth medium. At the same Cd concentration, PCs production was higher in roots than in bark, wood and leaves. Taken together, the majority of Cd accumulated by Populus × canescens roots was in the form of a Cd-PCs complex.