Influences of different ion channel inhibitors on the absorption of fluoride in tea plants (Camellia sinesis L.)

Abstract

The impacts of different ion channel inhibitors on the absorption and translocation of fluoride in tea plants were examined using the hydroponics method. The absorption of fluoride in tea plants increased after treatment with 0.5 mg/L water channel inhibitor (HgCl2), whereas no significant difference was demonstrated at concentrations of 2.0 and 10.0 mg/L HgCl2. Anionic channel inhibitors including NPPB and DIDS inhibited the absorption of fluoride in tea plants at concentrations of 10 and 20 μmol/L, respectively. When the concentration of NPPB in the solution was 10 μmol/L, the amount of fluoride accumulated in roots and in the whole tea plant were 135.44 and 356.22 mg/kg. These values were significantly lower (P < 0.01) than those in the control roots (340.36 mg/kg) and in the whole tea plant (758.19 mg/kg), respectively. At 20 μmol/L DIDS in the solution, the quantity of fluoride accumulated in the tea roots was 235.85 mg/kg, which was significantly lower (P < 0.01) than that in the control treatments (340.36 mg/kg). TEACl inhibited absorption of Al–F complexes in tea plants when the Al–F ratio was 1:2, but had no significant impact on the accumulation of Al–F complexes in tea plants when the Al–F ratio was 1:1. These results indicated that anionic and cationic channels may be important pathways for the entry of fluoride into tea plants.