Bioavailability and oxidative stress of cadmium to crops

摘要

Uptake of cadmium (Cd) by various vegetables at Jiangsu Province, where the total concentrations of Cd in the soils exceed corresponding guideline, was investigated and results showed that the concentration of Cd in some vegetables was not beyond the standards. To further investigate the bioavailability of Cd in soil to plants, diffusive gradient in thin films technique (DGT) was employed to study the uptake of Cd by rice. Results showed that Cd concentrations measured by DGT had pretty good linear relationship with Cd concentrations in rice roots and grains, which suggested DGT was a promising technique used for predicting the uptake of Cd by rice. At the same time, wheat was used to investigate the biochemical response of plants to Cd stress. Free radicals in wheat leaves were determined by electron paramagnetic resonance (EPR) spectroscopy and results showed that free radicals first decreased then increased with increasing Cd concentrations. The lowest free radical level was found at 3.3mg·kg<'-1> Cd concentration. Some parameters of antioxidation system were also measured and results suggested that the detoxification mechanisms might not be same for high and low Cd stress.