The Physiology of Sugar-Cane III. Characteristics of Sugar Uptake in Slices of Mature and Immature Storage Tissue

Abstract

Sugar uptake by slices of sugar-cane storage tissue took place in two stages. The initial uptake reached an equilibrium within 1 hr, the level being proportional to the external sugar concentration, independent of the sugar, and unaffected by anaerobic conditions. This sugar diffused out rapidly when the tissue was placed in water. It was thus contained in the apparent free space, 10-20 per cent. of the tissue volume. The secondary uptake continued up to 60 hr at a slow, constant rate, 1-5 mgjgjday, independent of sugar concentration above 2· 0 per cent., dependent on the sugar, and inhibited by anaerobic conditions. This sugar did not diffuse out when the tissue was placed in water. It was concluded that the secondary uptake was an active accumulation process.