Abstract
Our previous studies using cultured tobacco cells revealed that responses to aluminum (Al) ion for up to 24 h can be separated into two parts, early phase (from a start to about 6 h) and late phase (after 6 h), and that most responses related to toxicity occur during the late phase. In addition, cellular content of salicylic acid (SA) increases during the late phase. In this study, we examined if the Al-induced SA induces secondarily other responses. The bacterial gene NahG encoding salicylate hydroxylase removes SA. The NahG transformants of cultured cells and roots were compared Al responses with their non-transformants, respectively. Our results suggest that the SA in cultured cells partly causes callose production, but not the decrease in growth capability. In root system, it seems that SA contributes partly to callose production and root growth inhibition only after long exposure to Al for several days.
