Abstract
Potassium ion (K+) is one of the fundamental mineral nutrients for plant growth and is involved in cell elongation and expansion through osmotic regulations in plant cells. In addition, K+ uptake through K+ channels is necessary for proper cell cycle progression. Therefore, in this study, we examined the role of K+ in cell division and cell cycle progression of tobacco BY-2 cells. When we measured the cell osmotic pressure with plasmolysis method and a pressure probe, it was high in the elongating cells and low in the dividing ones. Subsequently, when we examined the effect of cytoplasmic alkalizing reagents, they restored the decreased cell division rate and the delay in cell cycle progression observed in the condition of K+ depletion. Therefore, K+ will be involved in cytoplasmic alkalization in cell division and cell cycle progression rather than in the regulation of cell osmotic pressure.
