Abstract: A hydroponic experiment was conducted to study the effects of cell division inhibitor maleic hydrazide (MH) on the physiological and biochemical characteristics of Tagetes erecta L., and the Cd accumulation in T. erecta leaves at different positions under the stress of 0.1 mg Cd·L^-1. Meanwhile, the Scontaining compounds cysteine (Cys) and glutathione (GSH) were foliar-sprayed to investigate their effects on the Cd accumulation. The results showed that adding 4 mmol MH·L^-1 to the culture solution had no obvious effects on the malondialdehyde (MDA) content and nitrate reductase and superoxide dismutase activities of T. erecta. In the control (without MH addition), the Cd concentration of top part leaves in consecutive three days increased from 0.81 to 4.89 mg·kg^-1, while that of mid and bottom part leaves increased from 0.24 and 0.32 mg·kg^-1 to 1.34 and 1.71 mg·kg^-1, respectively, illustrating that Cd first accumulated in top part leaves, i.e., the growth point of the plant. Adding MH to the solution inhibited the Cd accumulation in top part leaves significantly (P<0.05), but had less effects on the Cd accumulation in mid and bottom part leaves, compared with the control, which suggested that Cd accumulation in leaves had definite relations with cell division, in other words, exuberant cell division could promote leaf Cd accumulation. Foliar-spraying GSH alleviated the inhibitory effect of MH, while foliar-spraying Cys had less effect, suggesting that GSH participated in the metabolism of the plant, or interact with Cd, and thereby, the Cd level in plant shoots increased.

Key words: Organic wastes, Bio-degradation, CO₂ evolution, C/N ratio, Temperature, Water content, pH