The biosynthesis and metabolism of polyols. Sorbitol (d-glucitol) of plum leaves

Abstract

Plum leaves, which are rich in sorbitol, utilized a higher proportion of the 14c incorporated during photosynthesis in 14CO2 for sorbitol synthesis than for starch synthesis. Despite the large amounts present in the leaves, sorbitol is rapidly equilibrated with the primary products of photosynthesis; 15% was newly synthesized from Relabelled precursors in 3 hr. The method of Adcock (1957) for estimating sorbitol in biological material was adapted for use with leaf extracts. The sorbitol content of plum leaves under natural conditions was followed from 1 p.m. on one day to 9 a.m. the next day. The amount present remained constant at 110 mg/g of alcohol-in-soluble leaf residue (45 mg/g dry wt. of leaf).