Abstract
Ferrous (Fe2+) is a plant micro nutrient. On the other hand, excess ferrous is known to be toxic in cells. In this study, we examined a mechanism to keep a moderate ferrous uptake into tobacco BY-2 cells. After transfer of the tobacco BY-2 cells to a medium omitted divalent cations and applied 1.0 mg/L FeSO4, cell death in about 80 % of the cells were observed in 18 h. The Fe2+ influx is known to be mediated by Fe2+ transporters, which, its selectivity of Fe2+ is rather low and other divalent cations can be transported. Therefore, in addition to 1.0 mg/L FeSO4, when we applied 1.5 mM MgCl2 and 3.0 mM CaCl2 into the medium, DNA degradation and cell death is decreased and the amount of Fe2+ uptake was reduced. These results suggested that divalent cations such as Mg2+ and Ca2+ in the medium antagonized Fe2+ influx into cells.
