Processing Stripping Film Autoradiographs of Citrus Buds; Avoidance of Entrapped Air between Tissues and Developed Emulsion

Abstract

Autoradiography was used on paraffin sections for investigating DNA synthesis in vegetative and flower buds of Citrus sinensis (L.) Osbeck. We preferred stripping film to liquid emulsion to obtain a more uniform thickness of the silver grain layer, as this would not vary more than ±10%. Furthermore, Baserga and Nemeroff (1962) have observed a lower sensitivity of fluid emulsion in comparison to stripping film together with occasionally erratic grain count and a slightly higher incidence of mechanical fogging. However, on using the customary procedure it was found that close contact between the surface of the section and the developed emulsion was not maintained when dehydration and clearing was done in the usual manner. The following modifications were therefore introduced to prevent the formation of air pockets between these two layers.