ABSTRACT
Three examples of either natural or artificially induced alpha-amylase production by tissues of immature wheat grains are examined.
Aleurone tissue, predominantly that associated with the ventral portion of the grain appears to be responsible for the high levels of enzyme which can occur naturally in non-sprouted, pre-mature grains of the cv. Fenman.
Aleurone tissue of immature grains which is usually non-responsive to GA3, due to a block on gene expression at the transcription level, can be made to respond to the growth substance by various treatments such as drying and preincubation.
Scutellar tissues can also be induced to produce alpha-amylase if the embryo is excised from the immature grain. Unlike aleurone-derived alpha-amylase, enzyme produced by the scutellum is predominantly alpha-AMY 2 (low PI) isoenzymes. Each example presented reflects a breakdown of the temporal controls governing the switch from developmental to germinative mode with respect to alpha-amylase.
