Fluorometry of natural latex from Maclura pomifera

Abstract

Maclura pomifera is a small tree that produces rot-resistant wood and a strange fruit called an Osage orange which is bright green. The fruits contain a high content of latex with strong fluorescence in UV light, similar in color to the green-yellow fluorescence of uranyl glass. Measurements were made using a computer-assisted microscope with grating mono chromators in both excitation and emission pathways. A photomultiplier was calibrated using a tungsten illuminator, then a mercury illuminator was used to measure the fluorescence emission spectrum: the peak was at 530 nm (green-yellow). A xenon illuminator was used to measure the fluorescence excitation spectrum: the peak was at 380 nm (UV).