kinetics of a-amylase production are concerned, there are some important
differences between the isolated aleurone layer and the intact grain, especially
regarding the appearance of the high- and low-pi groups. The reasons for this
are not clear, but it could be because hormonal regulation within the intact grain
is different from that in the in vitro experiments with GA3—possibly attributable
to the fact that in the germinated grain GA1 appears to be the hormone involved.