Association between Water Status and Sucrose Metabolism in Cell Suspension Culture of Carrot

This work was undertaken to investigate the relationship between water status and sucrose metabolism of suspension culture of carrot (Daucus carota L.) cells. Embryogenic callus was induced on carrot hypocotyl in vitro. The cell suspension culture was then produced from this callus.In suspension culture, water potential and pH of the culture solution were decreased immediately after culture initiation to -0.62MPa and 4.5 respectively, but gradually increased from 2 days after culture initiation. Sucrose in suspension culture solution was found to be immediately hydrolyzed into glucose and fructose after the initiation of culture and disappeared within 2 days from culture initiation. The disappearance of sucrose from the culture solution within 2 days of culture initiation corresponds with increases in the activity of cell-wall-bound acid invertase. These results indicate that the decline of water potential of the culture solution at the early stages of carrot suspension culture was associated with sucrose metabolism as a result of an increase in acid invertase activity.