Abstract: A hydroponic culture was conducted to study the cadmium (Cd) accumulation in Tagetes erecta as affected by Sdeficiency, and to evaluate the roles of thiol compounds and organic acids in the Cd accumulation. After exposure to 0.1 mg Cd·L^-1 for 7 days, the Cd content in T. erecta root, stem, and leaf under S-deficiency decreased significantly by 47%, 38%, and 61%, respectively, compared with the control. S-deficiency had no significant effects on the synthesis of cysteine, γ-glutamyl cysteine, glutathione, and organic acids, and the three thiol compounds were all in lower levels. The synthesized phytochelatins (PCs) amount in S-deficient T. erecta root decreased significantly, which could be the main cause of the reduction of Cd accumulation in the plant. Among the plant organs, leaf had the highest organic acids content but no PCs, suggesting that the accumulated Cd in leaf was mainly bound by organic acids. All the results indicated that S-deficiency affected the synthesis of PCs in root, inducing the decrease of Cd accumulation in plant, but had less effects on the synthesis of organic acids that could possibly participate in the chelation of Cd in plant tissues.

Key words: Moss, Culture medium, Light culture, Growth hormone