EFFECT OF NITROGEN FERTILIZER ON GROWTH AND CADMIUM ACCUMULATION IN SEDUM ALFREDII HANCE

We characterized the effect of nitrogen (N) fertilizer on root morphology, photosynthetic pigments and cadmium (Cd) accumulation in a series of hydroponic experiments by using hyper-accumulating ecotype of Sedum alfredii H. (HE) and non-hyperaccumulating ecotype (NHE) plants. Cd accumulation in both ecotypes increased with increase of N levels until it reached the peak at 16 mM and then decreased suddenly. Among all the three N forms tested, ammonium sulfate [(NH4)2SO4] was found to be an optimum choice. Based on these findings, a pot experiment was also conducted to evaluate the effect of three N fertilizers on phytoextraction from a slightly Cd-contaminated soil by the hyper-accumulating plant Sedum alfredii H.