Uptake and Utilization of Sugars in Cultured Rice Cells

Abstract

Suspension cultured cells of rice (Oryza sativa) were grown in a medium containing sucrose. Sucrose was rapidly hydrolyzed extracellularly in the early stage of subculture with a concomitant decrease in the medium pH. The hydrolysis may be due to cell wall associated acid invertase and may be promoted by acidification of the medium. The resulting glucose and fructose seemed to be utilized equally. The cells grown on either sucrose, glucose or fructose contained each of these sugars and possessed cell wall associated invertase activity. Protoplasts prepared by cell wall degrading enzymes utilized preferentially glucose or fructose rather than sucrose. These results suggest that exogenous sucrose is hydrolyzed by the cell wall associated invertase to hexoses, which are then taken up and metabolized.