Background: Generally, tea plants are grown in acid soil which is rich in aluminum (Al) and fluoride (F). A recent publication showed that pretreatment with Al³⁺ promoted F accumulation in tea plants by increasing endogenous Ca²⁺ and calmodulin (CaM). A high level of F in tea leaves not only impairs tea quality but also might pose a health risk for people drinking tea regularly. Therefore it is important to try to find some clues which might be beneficial in controlling F accumulation in tea plants grown in acid soil (Al³⁺).

Results: It was found that diisothiocyanostilbene-2,2-disulfonic acid (DIDS) significantly reduced Al³⁺-promoted F accumulation in tea plants. Additionally, Al³⁺ plus DIDS treatment stimulated significantly higher Ca²⁺ efflux and decreased the CaM level in tea roots compared with Al³⁺ treatment. Besides, significantly higher depolarization of membrane potential was shown in tea roots treated with Al³⁺ plus DIDS than in those treated with Al³⁺, as well as higher net total H⁺ efflux and plasma membrane H⁺-ATPase activity.

Conclusion: Al³⁺-promoted F accumulation in tea plants was inhibited by an anion channel inhibitor DIDS. Ca²⁺/CaM and membrane potential depolarization may be the components involved in this process.