A system for imaging transverse distribution of scattered light and chlorophyll fluorescence in intact rice leaves

ABSTRACT In order to examine the transverse distribution of scattered light and chlorophyll fluorescence in intact rice leaves, a micro‐fluorescence imaging system was devised using a microscope, a CCD camera with an image intensifier, an Ar and a He‐Ne laser light source, an image processor, and a microcomputer. A laser light was projected vertically on to the surface of a rice leaf segment at a cut‐edge, and scattered light and induced fluorescence were observed at the cut‐section from a 90° angle to the axis of the laser beam. The intensity of scattered light showed a maximum at several micrometres depth from the leaf surface and a steep gradient afterwards. Fluorescence reached a maximum crossing with the decline curve of the scattered light. The maximum of fluorescence measured at 741 nm was observed at a greater depth from the leaf surface than that at 687 nm, suggesting that part of the fluorescence of the longer wavelength was emitted due to absorption of fluorescence of the shorter wavelength. Profiles of the scattered light and the chlorophyll fluorescence depended on leaf anatomy.