RECOVERY OF DIGITAL INFORMATION STORED IN LIVING PLANT LEAF PHOTOSYNTHETIC APPARATUS AS FLUORESCENCE SIGNALS

A CCD (charge-coupled device)-equipped, imaging spectroscopic instrume nt is discussed that can be reversible and rapidly reconfigured to ima ge photosynthetic fluorescence, allowing two-dimensional spatial estim ates of fluorescence quantum yield (Y'). Y' images of leaf areas with immediately functional photosynthetic apparatus appear smooth and unif orm and are much less affected by variations in chlorophyll content an d light path through the leaf, However, areas of the leaf where the ph otosynthetic apparatus has different light history, pathology, or othe r damage generate different Y' value images, This characteristic allow ed storage and recovery of images from leaves, Extending this finding, we prepared binary data coding for the value of pi to 99 decimal plac es (100 digits), on living leaves, The images containing the binary co des for these digits can be ''read'' by eye, because the human brain i nterprets visual data with great skill. However, it was necessary to e nhance the images to facilitate instrument ''reading'', A program was developed to enhance the images and ''read'' the data images with no e rrors. The photosynthetic mechanism involved (nonphotochemical quenchi ng), the role of leaf age and germplasm variation, and the potential a pplications of this finding in terms of bioelectronics are discussed.