登熟期의 降雨被害로 인한 麥酒麥 種子의 酵素 活性과 細胞化學的 變化

Enzyme activity and cytochemical changes of malting barley seeds affected by rainfall at harvest

The objective of this study was to clarify the reasons of low quality of malting barley at early germination stage caused by rainfall at harvest time. The rainfall undamaged seeds showed higher acid phospatase acivity during water imbibition than did the damaged seeds. The differences in the enzyme activity between the damaged and undamaged seeds became greater by 36 hour imbibition. When GA³was absent in the incubation medium the amount of acid phosphatase within the aleurone cells was higher than that released from the aleurone cells. However, with GA₃ the acid phosphatase released from the aleurone cell walls greatly increased after 36 hour incubation. The undamaged seeds released acid phosphatase more than the damaged seeds, and the difference was greater after 36 hour incubation. The seeds with embryos had higher α-amylase activity than did the seeds without embryos. The α-amylase activity of the undamaged seeds was gradually increased as the imbibition time progressed, but the damaged seeds did not show this tendency. The decrease in the α-amylase activity was directly proportional to the degree of rainfall damage at both incubation treatments with and without GA₃. The α-amylase released from the aleurone cell walls was greatly increased when GA₃ was present in the incubation medium, and the GA₃ effect was higher in the undamaged seed than the damaged seeds. The higher hydrolase activity was observed in the aleurone cell walls of the undamaged seeds. With longer imbibition time, the enzymes released from in the cell walls were detected in the starch granules of endosperm. The severe hydration of starch granules in endosperms of the damaged seeds was observed by scanning electron micrographs.