Ultrastructural localization of acid phosphatase activity in root tips by the p-(acetoxymercuric) aniline diazotate reagent and a comparison with a Gomori procedure.

The localization of acid phosphatase was studied in root tip cells of pea and mung bean by use of a heavy metal azo-dye technique. Diazotized p-(acetoxymercuric) aniline in a post-coupling procedure, using naphthol AS-BI phosphate as substrate, yielded a fine particulate reaction product within vacuoles, intercellular spaces, multivesicular bodies and at various sites throughout the cytoplasm of pea root cells and differentiating mung bean protoxylem cells. An ultrastructural comparison with a modified Gomori lead-salt precipitation method revealed differences in the subcellular location of beta-glycerophosphatase and naphthol AS-BI phosphatase. The distribution of acid phosphatases within plant meristematic cells is discussed.