into the surrounding medium, in the case of isolated layers) is GA3 dependent
(Fig. 8.14). Release of acid phosphatase commences 6-12 h after the introduction
of the hormone and occurs via areas of the cell wall that under the microscope
show obvious signs of digestion. It is likely, then, that the release of this enzyme
[and also of (1—»3)-[}-glucanase] is only indirectly attributable to the action of
GA3: first, synthesis of the cell-wall-hydrolyzing enzymes, the pentosanases, is
induced and these digest channels in the aleurone-layer cell wall to liberate
enzymes that are trapped [e.g., acid phosphatase, (1—»3)-P-glucanase))or en-
zymes whose release is impeded by the cell wall (e.g., a-amylase). It is likely
that the cell wall channels eventually provide a common path for the release of
all enzymes from the aleurone layer.