α-AMYLASE ISOENZYMES IN CANADIAN WHEAT CULTIVARS DURING KERNEL GROWTH AND MATURATION

Abstract

Polyacrylamide slab isoelectric focusing was used to examine the α-amylase isoenzymes present in wheat cultivars of diverse quality and genetic origin throughout kernel growth and maturation. Analyses were performed on whole kernels as well as anatomical parts of the kernel at four stages of development for each cultivar. A total of 22 α-amylase isoenzymes, separable into three distinct groups (GI, GII, and GIII), were detected in the immature wheat cultivars. The GIII isoenzymes closely resembled a similar group of isoenzymes previously considered present only in germinating wheat. The bulk of the activity in the early stages of kernel growth and maturation was found in the outer layers in the form of GI isoenzymes. As maturation proceeded, this activity decreased and small amounts of GIII isoenzymes appeared primarily in the endosperm, seedcoat and scutellum. Cultivar differences in α-amylase isoenzymes were noted.