Soil cadmium toxicity and nitrogen deposition differently affect growth and physiology in Toxicodendron vernicifluum seedlings

To ultimately determine whether different levels of soil nitrogen (N) deposition can modify the detrimental effects of cadmium (Cd), the seedlings of Toxicodendron vernicifluum (Strokes) F. A. Barkley were exposed to soil Cd stress (0, 5 and 15 mg kg-1 dry soil), N deposition (0, 13 and 40 mg kg-1 dry soil) and their combinations. Soil Cd stress caused damage in plant growth, photosynthesis and other physiological indexes, and in the ultrastructure of mesophyll cells. The effects of N deposition on growth, lipid peroxidation and enzyme activities depended on the relative amounts of N supplied. The combination of low N deposition and Cd stress was positive to plant growth, photosynthesis and enzyme activities, and it caused lower levels of Cd accumulation and lipid peroxidation compared with the effect of Cd stress alone. The combination of high N deposition and Cd stress led to a higher Cd accumulation and lipid peroxidation, and to lower enzyme activities, as compared with the effect of Cd stress alone. T. vernicifluum was found to be sensitive to soil Cd stress. Soil Cd had detrimental effects on T. vernicifluum seedlings, but the tolerance of T. vernicifluum to Cd increased under low N deposition.

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