Imunohistochemical Localization of α-Amylase in Cotyledons of Vigna mungo Seedlings

We studied the localization of alpha-amylase with indirect fluorescence microscopy in transversely sectioned cotyledons of Vigna mungo seedlings. Tissue sections were fixed in periodate-lysine-paraformaldehyde and treated with anti-alpha-amylase immunoglobulin G followed by fluorescein isothiocyanate labeled goat anti-rabbit immunoglobulin G. alpha-Amylase appeared in the cells farthest from vascular bundles on the second day of growth and appeared gradually closer to the vascular bundles as growth progressed. The pattern of alpha-amylase appearance was similar in detached cotyledons, indicating that attachment of the embryonic axis has no effect on this pattern. However, in attached cotyledons, alpha-amylase disappeared from the regions where starch grains had been digested, but in detached cotyledons there was no disappearance of alpha-amylase, and digestion was slower than in intact cotyledons.