Control of alpha-Amylase Development in Cotyledons during and following Germination of Mung Bean Seeds.

Developmental patterns of alpha-amylase in Vigna radiata cotyledons during and following germination were quite different depending on the differences in the treatments of cotyledons during the imbibitional stage. When axis-detached cotyledons were imbibed in water with seed-coats attached, alpha-amylase activity did not increase and remained low. On the other hand, when the cotyledons were imbibed in water after seed-coat removal, the enzyme activity increased markedly. If the axis was attached to the cotyledons, alpha-amylase showed a marked development even under the former imbibition conditions. These changes in the enzyme activity were in parallel with those in the enzyme content, and the content, in turn, was dependent upon the availability of mRNA for alpha-amylase. We propose that the regulation of the development of alpha-amylase in cotyledons may involve some factor(s) inhibitory to accumulation of alpha-amylase mRNA, which is present in dry cotyledons and can be removed from cotyledons by leakage or by the presence of the axis.