A specific method for the determination of soluble sugars in plant extracts using enzymatic analysis and its application to the sugar content of developing pear fruit buds.

A simple manual method for the routine analysis of glucose, fructose, mannose, galactose, and sucrose in plant material is described. The technique is demonstrated using various seeds known to form part of the diet of the bullfinch (Pyrrhula pyrrhula L.), a pest of commercial orchards in southeast England. The method involves the overnight extraction of the sugars with 62.5% aqueous methanol, followed by the conversion of the individual sugars to gluconate 6-phosphate (or, in the case of galactose, to galactono-gamma-lactone) by specific enzymes, and their determination spectrophotometrically.