Abstract
In cultured tobacco cells in calcium (Ca)-sucrose medium, Al causes cell elongation inhibition and other symptoms [reactive oxygen species production, callose secretion, cell death]. In this study, the mechanism of elongation inhibition and the relationship between these symptoms were examined. Cell elongation was estimated by measuring fresh weight (FW) of cell culture. After 3 to 6-h of the treatment time, the increases in FW, osmolality and soluble sugar content were observed in control cells, but not in Al-treated cells. The 14C-sucrose uptake was inhibited in Al-treated cells by 40% of the control level. When tobacco cells were incubated in sucrose-free Ca medium, the increases in FW, osmolality and soluble sugar were inhibited, indicating that sucrose uptake is necessary for water uptake and elongation. However, other Al symptoms were not induced. Taken together, we conclude that Al inhibits sucrose uptake, which leads to cell elongation inhibition, but not other Al symptoms.
