Free sugar fraction of the amylose-related mutants of maize

Abstract

The free sugar fraction of normal and amylose-related mutants of maize has been studied. The mutant waxy, characterized by a starch deprived of amylose, does not differ from the normal maize so far as free sugars are concerned. We report, however, the presence of maltose in waxy extracts, a disaccharide otherwise supposed to be absent in this genotype. Three high-amylose mutants (amylose extender, dull, and sugary-2) can be differentiated on the basis of the content of free sugars: dull and sugary-2 enhance amylose synthesis without inducing the presence of starch amylolytic products, while amylose extender accumulates a large quantity of maltose and maltooligosaccharides with a degree of polymerization between 3 and 8. In developing endosperm of amylose extender an abnormal amylolytic activity may be responsible for the observed abnormalities in free sugars and starch characteristics.