An experiment was conducted under hydroponic culture conditions to determine effects of nutrient deficiencies on cadmium (Cd) accumulation of Tagetes erecta L. and its possible mechanisms. Seedlings of similar size were pre-cultured in either N- or P- deprived nutrient solution for 7 days before exposure to 0.1 mg Cd L-1. The control plants had normal nutrient supply before and during Cd exposure. The plants were harveste after 7 days exposure to Cd. In N-deprived plants, Cd levels in roots, stems and roots were significantly reduced, which was consistent with a decrease of phytochelatins (PCs) in roots. Cd accumulation was the lowest in N-deficient plants, corresponding to substantial decreases in organic acids. In P-deprived plants, the obvious increase of Cd content in the root and stem and decrease of Cd content in the leaf accorded with increases of citric acid in the root and malic acid in the stem, supporting the suggestion that organic acids sequester soluble Cd and reduce Cd transport into the leaf.

Hydroponic experiments were carried out to study the effects of cell division inhibitor (Maleic hydrazide MH) and protein synthesis inhibitor（Cycloheximide CHI）on Cd accumulation in Tagetes erecta L and their possible mechanisms. Seedlings were exposed to 4 mmol L-1 MH or 3 µmol L-1 CHI in 0.1 mg L-1 Cd-containing solution for 3 days. After treatment, the Cd content in leaves was significantly (P<0.05) reduced under MH or CHI treatment, which was consistent with the decreased soluble protein contents in leaves, suggesting that protein synthesis plays a role in Cd accumulation in leaves of Tagetes erecta L. Both of the plant growth inhibitors led to increased Cd contents in roots compared with the control, corresponding with increased GSH, Cys or γEC content under MH or CHI treatment, indicating that those S-containing compounds may be related to the increased Cd content in roots under the plant growth inhibitor treatments. On the other hand, the two inhibitors increased the citric acid content in all the tissues of Tagetes erecta L except for that in leaves under CHI treatment. All the results suggest that protein synthesis may be responsible for Cd accumulation in leaves of Tagetes erecta L, while the S-containing compounds and organic acids are associated with Cd absorption in roots of Tagetes erecta L.