ABSTRACT
This chapter discusses some of the events following germination of barley grains which occur in the aleurone tissue attached to the growing seedling. It describes some of the major hormonal controls affecting expression of alpha-amylase genes in aleurone of barley, discussed the cellular mechanisms by which they operate, and attempted to relate these to germination and early seedling development. Whether the accumulation of abscisic acid (ABA)-inducible mRNAs in the aleurone of dehydrating seedlings occurs in response to ABA or to some other compound is not known. The changes in levels of alpha-amylase mRNA seen in the aleurone of developing seedlings are also seen in isolated aleurone layers treated with gametophytic factor (Ga). The observation that ABA can prevent the GA-induced synthesis of alpha-amylase indicates that aleurone is a tissue which is ABA-responsive, and raises the possibility that there may be a physiological role for its sensitivity to ABA.
