Cereal seed germination involves mobilization of the storage reserves in the starchy endosperm necessary to support seedling growth. The aleurone layer plays a key role in germination by responding to hormone signals from embryo and producing hydrolases that are secreted into the starchy endosperm for degradation of storage products. In the present work, the spatio-temporal patterns of ?-amylase and limit dextrinase (LD) were monitored in dissected aleurone layers from barley ( Hordeum vulgare ) seeds incubated for different times (6-72 h) in the presence of the hormones gibberellic acid (GA), abscisic acid (ABA) and salicylic acid (SA). The release of the proteins from the aleurone layer to the culture supernatant was also monitored by immunoblotting and the timing of the release of LD was found to differ from that of ?-amylase and suggested to depend on the programmed cell death (PCD). The release ?-amylase from aleurone layer to culture supernatant, however, was observed before PCD. The amount of total protein considerably decresead in aleurone layer treated with 1 mM SA while the amount of total protein in aleurone layer treated with 20 µM SA was even more than aleurone layer incubated in control medium which could be due to the stopping of protein secretion from aleurone layer in response SA and accumulation of proteins in aleurone layer. The aleurone layers were also treated with a combination of hormones GA+ABA and GA+SA and the appearance of ?-amylase and LD was investigated in both alurone layer and supernatant. The resutls show that even though the low amount of these two enzymes are present in aleurone layer treated with either ABA or SA, these enzyme can be secreted to supernatant only in the presence of GA. In addition in this study the activity of ascorbate peroxidase (APX) as one of the enzyme involved in the ascorbate-glutathione cycle was analyzed in soluble proteins from aleurone layer. The results show that the activity of APX is considerably decreased in aleurone layer teated with GA after 48 h whereas these changes was not observed in aleurone layer treated with either ABA or SA.