[Effects of sewage and Cd combined stress on metabolites of maize seedling].

To investigate the influences of sewage and cadmium combined stress on maize seedling metabolites, we took GC-MS metabonomics technology to analyze the metabolite species, content and metabolic pathways. A total of 50 kinds of metabolites were identified. Under single stress of Cd, the malic acid content in maize seedling decreased, the citric acid content increased significantly, and the tricarboxylic acid cycle was relatively stable. Under the combined stress, both malic acid and citric acid contents increased significantly, and the tricarboxylic acid cycle was inhibited. Both single Cd stress and combined stress of sewage and Cd, especially the latter, led to the decrease of glucose and the increase of those substances related to resistance, such as proline, putrescine, muscle and γ-aminobutyric acid, which indicated the photosynthesis was inhibited. It was concluded that sewage and cadmium combined stress influence on maize seedling metabolites mainly by inhibiting the tricarboxylic acid cycle and photosynthesis.