Abstract: An indoor pot experiment was conducted to study the effects of exogenous cysteine, glutamate, glycine, and their combinations on the Solanum nigrum pytoremediation of Cd. and PAHs contaminated soils. Single factor treatments with test amino acids had less effects on the S. nigrum plant height and its shoot dry weight (P>0.05), while multifactor treatments promoted the plant height and shoot dry weight significantly (P<0.05). All the treatments increased the Cd uptake and accumulation by the plants, with the extraction ratios of plant
 Cd in treatment cysteine reached as high as 1.80% and 1.83%, being 0.80-fold and 0.83-fold higher than the control, respectively. The combined application of cysteine, glutamate, and glycine promoted the removal of soil Cd and PAHs, with the best effect in treatment 0.3 mmol·kg^-1cysteine+0.3 mmol·kg^-1 glutamate+0.3 mmol·kg^-1 glycine, in which, the Cd concentration in plant shoot and the removal rate of soil PAHs increased by 1.26-fold and 4.46-fold, respectively, compared with the control. It was suggested that exogenous cysteine, glutamate, and glycine could promote the phytoremediation of low concentration Cd-PAHs contaminated soils, and have a promising future in contaminated soil phytoremediation.

Key words: Phytoplankton, Chlorophyll a, Primary productivity, Meiliang Bay