A STARCH-AGAR GEL METHOD FOR THE LOCALIZATION OF STARCH HYDROLYZING ENZYMES IN THE COTYLEDONS AND HYPOCOTYLS OF BEANS

A starch-agar gel assay was developed for the localization of enzyme activity in the cotyledons and hypocotyls of beans. The four major starch hydrolyzing enzymes, α-amylase, β-amylase, debranching enzyme and phosphorylase, were assayed with this technique using gels containing different substrates and buffers. Hypocotyls and cotyledons were sectioned by hand and the sections were incubated on the gel for varying lengths of time. Only α-amylase was observed to increase significantly. While virtually absent in ungerminated axes and hypocotyls from young seedlings, it increased first in the basal region and subsequently in progressively higher portions of the hypocotyl. High activities were first observed in the pith and later in the cortex. The increased activity was most obviously associated with the degradation of the pith, suggesting a regulation relative to cellular autolysis.