Impact of Cr and Zn on Growth, Biochemical and Physiological Parameters, and Metal Accumulation by Wheat and Barley Plants

摘要

The effect of different Cr and Zn concentrations in the soil on the development of Albares wheat and Pedrezuela barley plants at the physiological, biochemical, and structural levels was evaluated during the crop cycle in a greenhouse assay, as well as their potential use in phytoremediation strategies. The accumulation of Cr and Zn in plants was dose-dependent for both cultivars. The highest contents were found in root and the lowest in grain. In the Cr treatments, the decrease with respect to the control in the biomass, relative water content (RWC), chlorophyll content (Chl), and chlorophyll fluorescence values (Fv/Fm) was more pronounced in wheat than in barley. For the Zn treatments, the behavior was the opposite. Barley showed less tolerance to Zn concentrations although its higher translocation factor (TF) and greater biomass make this plant adequate to use in phytoremediation process in soil contaminated with Zn. The electron microscopy studies showed evidence that treatment with both Cr and Zn produced alterations in the cellular ultrastructure of the plant leaves. Cr and Zn induced the production of malondialdehyde (MDA) in both cultivars; the highest concentrations were observed in barley leaves. In general, the ascorbate peroxidase activity (APX) was higher in the plants exposed to metal treatments. The catalase activity (CAT) showed a different behavior depending on the metal studied. These results highlight the potential capacity of Albares wheat for use in the phytoremediation of soils contaminated by Zn and of Pedrezuela barley for use in Cr-and Zn-contaminated soils.