Sucrose Hydrolysis in Relation to Phloem Translocation in Beta vulgaris

Abstract

Asymmetrically labeled sucrose, 14C(fructosyl)sucrose, was used to determine whether sucrose undergoes extracellular hydrolysis during phloem translocation in the sugar beet, B. vulgaris. The metabolism of various sugars accumulated and translocated was determined in various regions of the plant. These processes were studied in detached regions as well as in the intact, translocating plant in the source leaf, along the translocation path, and in a rapidly growing sink leaf and storage beet. Unlike sucrose accumulation into the sink tissue of sugarcane, sucrose is neither hydrolyzed prior to phloem loading or during transit, nor is it extracellularly hydrolyzed during accumulation into sink leaves or the storage beet.