Interactive effects of cadmium and acid rain on photosynthetic light reaction in soybean seedlings

Interactive effects of cadmium (Cd2+) and acid rain on photosynthetic light reaction in soybean seedlings were investigated under hydroponic conditions. Single treatment with Cd2+ or acid rain and the combined treatment decreased the content of chlorophyll, Hill reaction rate, the activity of Mg2+-ATPase, maximal photochemical efficiency and maximal quantum yield, increased initial fluorescence and damaged the chloroplast structure in soybean seedlings. In the combined treatment, the change in the photosynthetic parameters and the damage of chloroplast structure were stronger than those of any single pollution. Meanwhile, Cd2+ and acid rain had the interactive effects on the test indices in soybean seedlings. The results indicated that the combined pollution of Cd2+ and acid rain aggravated the toxic effect of the single pollution of Cd2+ or acid rain on the photosynthetic parameters due to the serious damage to the chloroplast structure.

► Cd2+ decreased the photosynthetic parameters in soybean seedlings.
► Acid rain aggravated inhibition of Cd2+ on photosynthesis in soybean seedlings.
► Interactive effects depended on the concentration of Cd2+ and acid rain (H+).
► Damage in chloroplast structure decreased photosynthesis.