Combined effects of cadmium (Cd) and acid rain on physiological characteristics in Eleocarpus glabripetalus seedlings were investigated under controlled conditions. The single Cd treatment and the combined Cd and acid rain treatment increased growth at low Cd concentrations, while decreased growth and photosynthesis at high Cd2+ concentrations. A low Cd2+ concentration (50 mg kg-1) combined with different acid rain treatments increased the seedling biomass. A high Cd2+ concentration (100 mg kg-1) under different acid rain treatments significantly decreased the biomass, the Fe content, chlorophyll fluorescence and photosynthetic parameters. Relative electric conductivity, malondialdehyde (MDA) content and peroxidase (POD) activity were increased while the reduced glutathione (GSH) content and catalase (CAT) activity were significantly lower at high Cd2+ concentration under acid rain. The results indicated that the combination of a high concentration of Cd2+ and acid rain aggravated the toxic effect of Cd2+ or acid rain alone on the growth and physiological parameters of E. glabripetalus due to serious damage to the chloroplast structure. These results provide novel insights into the combined effects of Cd2+and acid rain on woody plants and might also serve as a guide to evaluate forest restoration and biological safety in areas with Cd2+and acid rain pollution.
Keywords: Acid rain; Cadmium; Combined effects; Elaeocarpus glabripetalus; Physiological responses.
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