Uptake and Utilization of Sugars in Cultured Rice Cells

Suspension cultured cells of rice (Oryza sativa) were grownin a medium containing sucrose. Sucrose was rapidly hydrolyzedextracellularly in the early stage of subculture with a concomitantdecrease in the medium pH. The hydrolysis may be due to cellwall associated acid invertase and may be promoted by acidificationof the medium. The resulting glucose and fructose seemed tobe utilized equally. The cells grown on either sucrose, glucoseor fructose contained each of these sugars and possessed cellwall associated invertase activity. Protoplasts prepared bycell wall degrading enzymes utilized preferentially glucoseor fructose rather than sucrose. These results suggest thatexogenous sucrose is hydrolyzed by the cell wall associatedinvertase to hexoses, which are then taken up and metabolized. (Received November 25, 1987; Accepted February 8, 1988)