Characterization of Peroxidases in Lignifying Peach Fruit Endocarp

Developing peach (Prunus persica L. Batsch ;Redskin') fruit were used to characterize the role of peroxidases in lignification. During development, the endocarp of these drupes becomes lignified while the mesocarp remains parenchymatous. Acidic peroxidase from lignifying endocarp were similar to those of the fleshy mesocarp. The endocarp had a larger amount and number of basic peroxidases than the mesocarp. Cultured peach leaf cells are thought to be lignified because their walls give a positive reaction with phloroglucinol-HCI. These cells also secreted a basic peroxidase. Peroxidases were difficult to extract from endocarp tissue as they lignified. This was also demonstrated by tissue printing on nitrocellulose. Flesh, but not endocarp peroxidase was evident in tissue prints. This suggests that tissue printing may fail to reveal the presence of enzymes which are firmly attached to the cell.