Localization of AquaDust optical signal. A) to C) Cryo-SEM micrograph of a A) maize leaf cross-section and the depth profile of acceptor dye emission (580 $±$ 10 nm) from fluorescence confocal cross-sections through B) adaxial and C) abaxial surfaces of maize leaf. Native autofluorescence from cytosol, cuticle, and chloroplast is false-colored as blue and AQD fluorescence is false-colored as red. See Supplementary Movie S1 for top-view, z-stack confocal micrographs.