DISTRIBUTION OF α-AMYLASE IN THE TRITICALE KERNEL DURING DEVELOPMENT

Seed of four triticale (Triticale hexaploide Lart.) cultivars, two wheat (Triticum aestivum L.) cultivars, and one rye (Secale cereale L.) cultivar were harvested at 4-day intervals from 6 to 42 days post-anthesis. Alpha-amylase activity was determined in the embryo, pericarp, aleurone, and endosperm of the seed. In all cases, the α-amylase activity in the embryo was low. The pericarp activity reached a maximum in all samples at approximately 10–15 days post-anthesis. Aleurone and endosperm activity remained low throughout the development period in all but one triticale cultivar. In triticale cultivar 6A 190, the aleurone and endosperm α-amylase activity remained low until approximately 20–25 days post-anthesis, at which point the activity increased to levels normally associated with sprouted grain. Light microscopic examination of the 6A 190 at 10 days post-anthesis showed that the starch in the inner portion of the pericarp was digested. At 22 days, all pericarp starch had disappeared. Specific lesions in the endosperm and aleurone cells were observed beyond 22 days. Areas of the endosperm where starch damage due to α-amylase could be seen were often associated with regions possessing necrotic tissue located between the aleurone and endosperm. In some areas, aleurone cells were completely absent.