Al³⁺-induced superoxide generation and its inhibition by Zn²⁺ and Mn²⁺ in tobacco cells

Abstract

Our previous research has shown that Mn²⁺ and Zn²⁺ inhibit the La³⁺-induced superoxide generation in tobacco (Nicotiana tabacum L., cell-line BY-2) cells. In this study, we observed the Al³⁺-induced generation of superoxide in tobacco BY-2 cell suspension culture, using a superoxide-specific Cypridina luciferin analog (CLA). We examined the effect of culture age on the Al³⁺-induced response and found that higher level of superoxide generation was induced in the young cell cultures (2 - 4 day-old) when the range of culture age between 2 and 12 days after subculturing was examined. We also examined the effects of ZnSO₄ and MnSO₄ on Al³⁺-induced superoxide generation. Results indicated that both Zn²⁺ and Mn²⁺ inhibit the superoxide generation. Zn²⁺ at low dose (ca. 0.1 mM) and Mn²⁺ at high dose (10 - 30 mM) inhibited the Al-induced response by 50%.