Chaofan Sun¹, Tianran Zhao¹, Xiaojing Wang¹, Kejie Han^{1, 2}, Huicheng Xie^{1, 2,}

In order to investigate the practicability to phytoremediation fluoride in wastewater by sunflower, experiment was carried out by hydroponic culture with oilseed type sunflower (Helianthus annuus L.) seedlings. The results indicated that fluorine concentrations in organs of sunflower were significantly increased with increasing solution concentrations and the content order of fluorine in sunflower organs was: roots> leaves> stems. The translocation factor was between 0.045-0.095, indicating that sunflower cannot effectively transport fluorine ions from the roots to the aerial part. The P_n, G_s and T_r of sunflower leaves decreased significantly with the increase of fluoride concentration. The C_i first decreased and then increased with the increase of fluoride concentration. Those results showed that the main reason for the decrease of P_n was the stomatal limitation when the F^-1 concentration was between 0 and 20 mg L^-1, and the non-stomatal limitation was the main reason for the decrease of P_n when the concentration of F^-1 was between 50 and 150 mg L^-1. The maximum concentration of fluoride ions in which sunflower can endure was 87 mg L^-1.

sunflower, fluorion, enrichment, photosynthethesis