Temperature affects cadmium-induced phytotoxicity involved in subcellular cadmium distribution and oxidative stress in wheat roots.

In this study, the effect of temperature on Cd toxicity to wheat roots was evaluated in terms of the relative root length and subcellular distribution of Cd as well as the antioxidant enzymatic activities after exposed to Cd for 72 h under different temperatures. The result showed that the EC(50)-values for the relative root length were 9.24, 4.91 and 3.62 μM Cd at 18, 25 and 30°C, respectively. The Cd concentrations in the cellular metal-sensitive fraction or the potentially toxic fraction (cell debris fraction-Cd) were well correlated with the toxicity of Cd. Interestingly, the superoxide dismutase (SOD) and catalase (CAT) in wheat roots without Cd exposure were increased at 18°C compared to those at 25°C, while decreased at 30°C. The CAT activities decreased with increasing Cd level at 25 and 18°C but did not show the same change at 30°C, which could be explained by the subcellular distribution of Cd.