Histochemistry of carboxyl esterases in the broad bean root tip with indoxyl substrates.

The possibility of the use of indoxyl substrates for enzyme localization in plant material was tested and proved. Studying the localization of the carboxyl esterase in broad ben root tip a) the time course of the indigogenic reaction was investigated, b) the concentration of the ferro/ferri redox buffer was examined, c) various substances were used to control the indigogenic visualizing reaction, d) the azocoupling procedure was applied with indoxyl substrates, e) unhalogenated and halogenated substrates were tried, and, finally, f) acetate and butyrate were employed in the indigogenic procedure. Using the last mentioned (f) trial the existence and localization was verified in the material tested of carboxyl esterase fractions recognized there previously on the basis of azocoupling reactions with naphtholic substrates.